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Cross-Domain Unit Mapping Ontology

AI Measurement Semantics
Authors: MArk Anthony Higgins - Sky Recursive Ai
© Mark Anthony Higgins 11 October 2025
Revised Date: 16 September 2026
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# Cross-Domain Unit Mapping Ontology — Flow Algebra

URL: https://kirethresearch.org/booksai-core/ontologies/mathematical-ontologies/measurement-units-ontologies/ai-measurement-semantics/cross-domain-unit-mapping-ontology.html

FLOW CrossDomainUnitMappingOntology {

  DOMAIN:
    Mathematical Ontologies
    -> Measurement & Units Ontologies
    -> AI Measurement Semantics
    -> Cross-Domain Unit Mapping Ontology

  PURPOSE:
    Represent the semantic mapping of measurement units, quantity kinds, dimensions, scales, reference states and measurement conventions across scientific, engineering and computational domains. The ontology enables AI systems to determine when two unit expressions are exactly convertible, contextually convertible, dimensionally compatible but semantically distinct, operationally defined, reference-dependent or incompatible. It models SI and non-SI units, domain-specific units, prefixes, compound units, affine and logarithmic scales, count and ratio quantities, chemical and biological concentration conventions, astronomical units, earth-science units, engineering conventions, temporal units, information units, coordinate-dependent quantities, uncertainty propagation, provenance, versioning and machine-readable mapping rules while preventing dimensional similarity from being mistaken for semantic equivalence.

  ENTITY CrossDomainUnitMapping {
    TYPE: SemanticUnitInteroperabilityFramework

    PROPERTIES:
      maps_units
      maps_quantity_kinds
      maps_dimensions
      maps_scales
      maps_reference_states
      maps_domain_conventions
      validates_conversion
      propagates_uncertainty
      preserves_provenance
      preserves_versions
      exposes_ambiguity
  }

  ENTITY UnitMapping {
    TYPE: TypedSemanticRelation

    COMPONENTS:
      source_unit
      target_unit
      source_quantity_kind
      target_quantity_kind
      mapping_type
      conversion_function
      constraints
      uncertainty
      provenance
  }

  ENTITY DomainUnit {
    TYPE: MeasurementUnit

    PROPERTIES:
      identifier
      name
      symbol
      domain
      quantity_kind
      dimension
      scale
      offset
      reference_state
      definition_source
  }

  ENTITY MappingContext {
    TYPE: ConversionContext

    POSSIBLE:
      physical_conditions
      chemical_composition
      reference_temperature
      reference_pressure
      gravitational_context
      coordinate_frame
      calendar
      domain_standard
      measurement_method
  }

  MAPPING_TYPE_MODEL {
    possible:
      exact_identity
      exact_linear_conversion
      defined_linear_conversion
      affine_conversion
      logarithmic_conversion
      contextual_conversion
      model_based_conversion
      semantic_alignment_without_conversion
      dimensionally_compatible_but_semantically_distinct
      incompatible

    RULE:
      mapping_type MUST be explicit
  }

  EXACT_IDENTITY_MODEL {
    source:
      canonical_unit_A

    target:
      canonical_unit_B

    condition:
      same_definition_andquantity_kind

    RULE:
      lexical_difference MAY coexist_withsemantic_identity
  }

  LINEAR_CONVERSION_MODEL {
    source_value:
      x

    target_value:
      y =
        k*x

    RULE:
      factor_exactness MUST be preserved
  }

  AFFINE_CONVERSION_MODEL {
    y =
      a*x+b

    RULE:
      affine_mapping MUST distinguish_absolute_values_fromdifferences
  }

  LOGARITHMIC_CONVERSION_MODEL {
    generic:
      L =
        k*log_b(Q/Q_ref)

    REQUIRE:
      reference_quantity
      logarithm_base
      multiplier
      quantity_kind

    RULE:
      logarithmic_units MUST not_be processed_asordinary_linear_units
  }

  CONTEXTUAL_CONVERSION_MODEL {
    y =
      f(x,c_1,...,c_n)

    RULE:
      required_context_parameters MUST not_be invented
  }

  MODEL_BASED_MAPPING_MODEL {
    target:
      derived_fromsource_usingphysical_or empirical_model

    RULE:
      model_based_mapping != unit_conversion_instrict_metrological_sense
  }

  SEMANTIC_ALIGNMENT_MODEL {
    source_entity:
      maps_to_target_entity

    relation:
      exact
      broader
      narrower
      related

    RULE:
      ontology_alignment MAY exist_withoutnumeric_conversion
  }

  DIMENSION_MODEL {
    canonical:
      L^a*M^b*T^c*I^d*Theta^e*N^f*J^g

    RULE:
      dimension != quantity_kind
  }

  DIMENSIONAL_COMPATIBILITY_MODEL {
    source_dimension:
      D_s

    target_dimension:
      D_t

    direct_unit_conversion_requires:
      D_s =
        D_t

    RULE:
      equal_dimensions_are_not_sufficient_forsemantic_equivalence
  }

  SAME_DIMENSION_DIFFERENT_KIND_MODEL {
    examples:
      energy_vs_torque
      frequency_vs_radioactivity
      absorbed_dose_vs_dose_equivalent
      plane_angle_vs_dimensionless_ratio

    RULE:
      AI MUST preserve_quantity_kind
  }

  QUANTITY_KIND_MAPPING_MODEL {
    source:
      quantity_kind_A

    target:
      quantity_kind_B

    possible:
      same
      equivalent_undercontext
      related_byequation
      semantically_distinct

    RULE:
      unit_mapping MUST not silently_change_quantity_kind
  }

  SI_MODEL {
    system:
      International_System_of_Units

    RULE:
      SI_unit_definitions SHOULD be canonical_reference_whenappropriate
  }

  NON_SI_MODEL {
    unit:
      outside_SI

    possible:
      accepted_with_SI
      domain_specific
      customary
      historical

    RULE:
      status MUST be version_anddomain_resolved
  }

  PREFIX_MODEL {
    prefixed_unit:
      prefix*unit

    factor:
      10^n
      under_SI_decimal_prefix_context

    RULE:
      prefix_case_andattachment MUST be preserved
  }

  BINARY_PREFIX_MODEL {
    possible:
      kibi
      mebi
      gibi
      tebi
      pebi
      exbi

    factor:
      2^(10n)

    RULE:
      binary_prefix != decimal_SI_prefix
  }

  COMPOUND_UNIT_MODEL {
    expression:
      products
      quotients
      powers

    RULE:
      conversion_factor MUST propagate_throughentire_expression
  }

  POWERED_UNIT_MODEL {
    source:
      (k*u)^n

    relation:
      k^n*u^n

    RULE:
      prefix_factor MUST be exponentiated_withunit
  }

  MASS_MAPPING_MODEL {
    SI:
      kilogram

    possible:
      gram
      tonne
      pound
      ounce

    RULE:
      mass_unit_mapping MUST not_be confused_withforce
  }

  FORCE_MASS_DISTINCTION_MODEL {
    mass:
      dimension_M

    force:
      dimension_M*L*T^-2

    RULE:
      pound_mass_andpound_force MUST be explicitly_distinguished
  }

  LENGTH_MAPPING_MODEL {
    possible:
      metre
      centimetre
      millimetre
      kilometre
      inch
      foot
      yard
      mile
      nautical_mile

    RULE:
      definition_source_andexact_factor SHOULD be preserved
  }

  AREA_MAPPING_MODEL {
    relation:
      length_factor_squared

    RULE:
      linear_conversion_factor MUST not_be applied_unpowered_toarea
  }

  VOLUME_MAPPING_MODEL {
    relation:
      length_factor_cubed

    possible:
      cubic_metre
      litre
      millilitre
      gallon
      fluid_ounce

    RULE:
      gallon_orfluid_ounce_requires_system_resolution
  }

  IMPERIAL_US_DISTINCTION_MODEL {
    ambiguous_names:
      gallon
      pint
      fluid_ounce
      ton

    RULE:
      jurisdiction_orunit_system MUST be resolved
  }

  TEMPERATURE_MAPPING_MODEL {
    scales:
      kelvin
      degree_Celsius
      degree_Fahrenheit
      Rankine

    RULE:
      temperature_scale_value_conversion_is_affine
  }

  TEMPERATURE_DIFFERENCE_MODEL {
    interval:
      delta_temperature

    RULE:
      offsets_do_not_apply_to_temperature_differences
  }

  PRESSURE_MAPPING_MODEL {
    possible:
      pascal
      kilopascal
      bar
      atmosphere
      torr
      psi

    RULE:
      gauge_absolute_anddifferential_pressure MUST be distinguished
  }

  PRESSURE_REFERENCE_MODEL {
    possible:
      absolute
      gauge
      differential

    RULE:
      gauge_toabsolute_conversion_requires_reference_pressure
  }

  ENERGY_MAPPING_MODEL {
    possible:
      joule
      kilojoule
      calorie
      kilocalorie
      watt_hour
      electronvolt
      BTU

    RULE:
      calorie_andBTU_definitions MAY require_variant_resolution
  }

  POWER_MAPPING_MODEL {
    possible:
      watt
      kilowatt
      horsepower

    RULE:
      horsepower_variant MUST be identified
  }

  TIME_MAPPING_MODEL {
    possible:
      second
      minute
      hour
      day

    RULE:
      fixed_duration_units MUST be distinguished_fromcalendar_units
  }

  CALENDAR_TIME_MODEL {
    possible:
      month
      year

    RULE:
      conversion_to_seconds_requires_calendar_orconvention_context
  }

  FREQUENCY_MODEL {
    unit:
      hertz

    dimension:
      T^-1

    RULE:
      Hz_semantics != Bq_semantics
  }

  ANGULAR_FREQUENCY_MODEL {
    quantity:
      angular_frequency

    common:
      rad/s

    relation:
      omega =
        2*pi*f

    RULE:
      angular_frequency_andcyclic_frequency_are_related_quantity_kinds_notidentical_numeric_units
  }

  ANGLE_MODEL {
    possible:
      radian
      degree
      arcminute
      arcsecond

    RULE:
      angle_is_dimensionless_inSI_dimension_system_butretains_quantity_kind
  }

  SPEED_MODEL {
    possible:
      m/s
      km/h
      mph
      knot

    RULE:
      velocity_vector_andspeed_scalar MUST be distinguished
  }

  ACCELERATION_MODEL {
    possible:
      m/s^2
      gal
      standard_gravity_multiple

    RULE:
      symbol_g MAY representquantity_orstandard_gravity_context_andmust_be resolved
  }

  STANDARD_GRAVITY_MODEL {
    g_n:
      defined_reference_acceleration

    RULE:
      local_gravity != standard_gravity
  }

  TORQUE_ENERGY_MODEL {
    shared_dimension:
      M*L^2*T^-2

    RULE:
      N*m_for_torque MUST not_be canonicalised_tojoule_whenquantity_kind_is_torque
  }

  ELECTRICAL_MODEL {
    quantities:
      voltage
      current
      resistance
      conductance
      charge
      capacitance
      inductance

    RULE:
      mapping MUST preserve_quantity_kind
  }

  MAGNETIC_MODEL {
    quantities:
      magnetic_flux
      magnetic_flux_density
      magnetic_field_strength

    RULE:
      tesla_gauss_andfield_strength_units MUST be quantity-aware
  }

  PHOTOMETRIC_MODEL {
    quantities:
      luminous_intensity
      luminous_flux
      illuminance
      luminance

    RULE:
      radiometric_andphotometric_quantities MUST not_be directly_equated
  }

  RADIOMETRIC_MODEL {
    quantities:
      radiant_flux
      irradiance
      radiance

    RULE:
      photometric_conversion_requires_spectral_weighting_context
  }

  CHEMICAL_CONCENTRATION_MODEL {
    possible:
      molarity
      molality
      mass_concentration
      mass_fraction
      amount_fraction
      volume_fraction

    RULE:
      concentration_quantity_kinds_are_not_interchangeable_byunit_scaling_alone
  }

  MOLARITY_MOLALITY_MODEL {
    molarity:
      amount/volume_solution

    molality:
      amount/mass_solvent

    RULE:
      conversion_requires_density_andcomposition_context
  }

  MASS_FRACTION_MODEL {
    w =
      mass_component/mass_total

    dimension:
      1

    RULE:
      percent_by_mass MUST retain_fraction_basis
  }

  VOLUME_FRACTION_MODEL {
    phi =
      volume_component/volume_total

    dimension:
      1

    RULE:
      volume_fraction MAY depend_onreference_temperature_andpressure
  }

  AMOUNT_FRACTION_MODEL {
    x =
      amount_component/amount_total

    dimension:
      1

    RULE:
      amount_fraction != mass_fraction
  }

  PPM_MODEL {
    token:
      ppm

    possible:
      dimensionless_fraction
      mass_fraction
      volume_fraction
      amount_fraction

    RULE:
      ppm_requires_basis_resolution
  }

  PPB_MODEL {
    token:
      ppb

    RULE:
      scale_convention_andfraction_basis MUST be explicit
  }

  GAS_CONCENTRATION_MODEL {
    conversion:
      volume_oramount_fraction_to_mass_concentration

    requires:
      molar_mass
      temperature
      pressure
      gas_model

    RULE:
      conversion_is_contextual_notpure_unit_scaling
  }

  BIOLOGICAL_CONCENTRATION_MODEL {
    possible:
      cells_per_volume
      copies_per_volume
      mass_pervolume
      activity_pervolume

    RULE:
      entity_type_andmeasurement_method MUST be preserved
  }

  CELL_COUNT_MODEL {
    unit:
      cells
      cells_pervolume
      cells_perarea

    RULE:
      count_entity_identity MUST be explicit
  }

  ENZYME_ACTIVITY_MODEL {
    possible:
      katal
      enzyme_unit

    RULE:
      enzyme_unit_conversion_requires_declared_definition
  }

  CLINICAL_UNIT_MODEL {
    possible:
      conventional_units
      SI_units

    RULE:
      analyte_specific_molar_mass_orconversion_relation MAY be required
  }

  PH_MODEL {
    quantity:
      logarithmic_measure_ofhydrogen_ion_activity_underdefined_convention

    RULE:
      pH_is_not_linear_concentration_unit
  }

  DECIBEL_MODEL {
    logarithmic:
      level_relative_to reference

    RULE:
      power_andamplitude_ratio_forms_use_different_multipliers
  }

  SOUND_PRESSURE_LEVEL_MODEL {
    L_p =
      20*log10(p/p_ref)

    RULE:
      reference_pressure_andmedium_context MUST be preserved
  }

  STELLAR_MAGNITUDE_MODEL {
    logarithmic_scale:
      brightness_related

    RULE:
      magnitude_system_andzero_point MUST be identified
  }

  SEISMIC_MAGNITUDE_MODEL {
    logarithmic_or empirical_scale:
      earthquake_size

    RULE:
      magnitude_scale_type MUST be explicit
  }

  EARTH_SCIENCE_MODEL {
    possible:
      rainfall_depth
      river_discharge
      soil_moisture
      elevation
      depth
      atmospheric_pressure
      wind_speed

    RULE:
      geodetic_vertical_reference_andmeasurement_basis MAY be required
  }

  RAINFALL_MODEL {
    depth:
      length_unit_overaccumulation_period

    RULE:
      rainfall_depth != rainfall_rate
  }

  RIVER_DISCHARGE_MODEL {
    quantity:
      volume/time

    possible:
      m^3/s
      litre/s
      cubic_foot/s

    RULE:
      flow_rate_quantity_kind MUST be explicit
  }

  SOIL_MOISTURE_MODEL {
    possible:
      volumetric_water_content
      gravimetric_water_content

    RULE:
      basis MUST be identified_beforemapping
  }

  ELEVATION_MODEL {
    quantity:
      vertical_position_relative_to datum

    RULE:
      datum MUST be preserved
  }

  ASTRONOMICAL_DISTANCE_MODEL {
    possible:
      metre
      kilometre
      astronomical_unit
      light_year
      parsec

    RULE:
      distance_unit_definition_andversion SHOULD be preserved
  }

  ASTRONOMICAL_UNIT_MODEL {
    symbol:
      au

    RULE:
      exact_definition_context SHOULD be preserved
  }

  LIGHT_YEAR_MODEL {
    distance:
      light_travel_distance_forJulian_year_underdefined_c

    RULE:
      year_definition MUST be explicit
  }

  PARSEC_MODEL {
    geometric_definition:
      distance_corresponding_to parallax_relation

    RULE:
      exact_conversion_reference SHOULD be version_resolved
  }

  REDSHIFT_MODEL {
    dimension:
      1

    RULE:
      redshift_to_distance_requires_cosmological_model
  }

  LUMINOSITY_MODEL {
    quantity:
      power

    RULE:
      luminosity_andobserved_flux_require_distance_andgeometry_relation
  }

  ENGINEERING_MODEL {
    conventions:
      stress
      strain
      torque
      power
      pressure
      flow
      rotational_speed

    RULE:
      engineering_quantity_convention MUST accompanyunit
  }

  RPM_MODEL {
    quantity:
      rotational_frequency_orrate

    relation:
      revolutions_perminute

    RULE:
      conversion_toangular_velocity_requires_2*pi_relation
  }

  STRAIN_MODEL {
    dimension:
      1

    possible:
      ratio
      percent
      microstrain

    RULE:
      microstrain_is_scaling_ofdimensionless_strain
  }

  INFORMATION_UNIT_MODEL {
    possible:
      bit
      byte
      kilobyte
      megabyte
      kibibyte
      mebibyte

    RULE:
      decimal_andbinary_prefixes MUST be distinguished
  }

  DATA_RATE_MODEL {
    possible:
      bit/s
      byte/s

    RULE:
      bit_byte_andprefix_semantics MUST be preserved
  }

  COUNT_MODEL {
    quantity:
      number_ofentities

    dimension:
      1

    RULE:
      count_entity_type MUST be preserved
  }

  PERCENTAGE_MODEL {
    value:
      fraction*100

    RULE:
      percentage_basis MUST be explicit
  }

  DIMENSIONLESS_MAPPING_MODEL {
    source:
      ratio_scale

    target:
      percent_ppm_ppb_orunit_one

    RULE:
      dimensionless_mapping_requires_same_quantity_kind_andbasis
  }

  REFERENCE_CONDITION_MODEL {
    fields:
      temperature
      pressure
      humidity
      composition
      gravity
      datum
      epoch

    RULE:
      context-dependent mapping MUST carry_reference_conditions
  }

  DENSITY_DEPENDENT_MODEL {
    conversion:
      mass <-> volume

    requires:
      density

    RULE:
      this_is_quantity_conversion_usingadditional_measurement_notunit_conversion
  }

  MOLAR_MASS_MODEL {
    conversion:
      amount <-> mass

    requires:
      molar_mass

    RULE:
      chemical_identity_andmolar_mass_source MUST be preserved
  }

  STOICHIOMETRIC_MODEL {
    conversion:
      amount_ofA <-> amount_ofB

    requires:
      reaction_equation
      stoichiometric_coefficients

    RULE:
      stoichiometric_conversion != unit_conversion
  }

  COORDINATE_MAPPING_MODEL {
    source:
      vector_orposition_inframe_A

    target:
      frame_B

    RULE:
      coordinate_transformation != unit_conversion
  }

  UNCERTAINTY_PROPAGATION_MODEL {
    source:
      x
      context_parameters:
        c

    target:
      y =
        f(x,c)

    first_order:
      u_y^2 =
        J*Sigma*J^T

    RULE:
      context_parameter_uncertainties_andcovariances MUST be included_whenmaterial
  }

  EXACT_FACTOR_MODEL {
    conversion_factor:
      defined_exactly

    RULE:
      exact_factor_adds_no_measurement_uncertainty
  }

  MEASURED_FACTOR_MODEL {
    conversion_factor:
      derived_frommeasurement_orproperty

    RULE:
      factor_uncertainty MUST propagate
  }

  CONSTANT_MODEL {
    possible:
      exact_defining_constant
      recommended_physical_constant
      empirical_constant

    RULE:
      exactness_version_andprovenance MUST be preserved
  }

  ROUND_TRIP_MODEL {
    source:
      A

    convert:
      A -> B -> A

    expectation:
      original_value_within_numeric_andcontextual_tolerance

    RULE:
      round_trip_supports_mapping_validation
  }

  CANONICAL_UNIT_MODEL {
    quantity_kind:
      preferred_machine_reasoning_unit

    RULE:
      canonicalisation MUST preserve_original_unit_andrepresentation
  }

  NORMAL_FORM_MODEL {
    unit_expression:
      base_dimensions
      scale
      offset
      semantic_quantity_kind

    RULE:
      normal_form MUST not erase_special_quantity_kind_semantics
  }

  UNIT_IDENTIFIER_MODEL {
    fields:
      namespace
      identifier
      version

    RULE:
      identifier_is_preferred_overambiguous_display_symbol
  }

  SYMBOL_MODEL {
    unit_symbol:
      case_sensitive

    RULE:
      symbol_case MUST be preserved
  }

  ALIAS_MODEL {
    unit:
      may_have_multiple_names_or spellings

    RULE:
      alias != distinct_unit_when_definition_identity_established
  }

  HOMONYM_MODEL {
    same_name_or symbol:
      different_units

    RULE:
      homonym_requires_domain_or system_resolution
  }

  MULTILINGUAL_MODEL {
    unit_name:
      language_specific_label

    RULE:
      translation MUST preserve_canonical_unit_identity
  }

  LOCALE_MODEL {
    concerns:
      decimal_marker
      thousands_separator
      spelling
      customary_unit_usage

    RULE:
      locale_must_not_change_canonical_quantity_semantics
  }

  DOMAIN_MAPPING_MODEL {
    source_domain:
      A

    target_domain:
      B

    mapping:
      unit
      quantity_kind
      reference_conditions
      terminology

    RULE:
      cross_domain_mapping MUST preserve_domain_assumptions
  }

  ONTOLOGY_ALIGNMENT_MODEL {
    source_unit_entity:
      target_unit_entity

    relations:
      exact
      equivalent_undercontext
      broader
      narrower
      related
      incompatible

    RULE:
      exact_mapping_requires_definition_quantity_kind_scale_offset_andreference_compatibility
  }

  SEMANTIC_EQUIVALENCE_MODEL {
    evaluate:
      unit_definition
      quantity_kind
      dimension
      scale
      offset
      reference_state
      domain

    RULE:
      same_conversion_factor != semantic_equivalence
  }

  MAPPING_CONFIDENCE_MODEL {
    factors:
      identifier_match
      definition_match
      quantity_kind_match
      dimension_match
      context_completeness
      source_authority
      provenance

    RULE:
      mapping_confidence != measurement_uncertainty
  }

  AMBIGUITY_MODEL {
    possible:
      unit_system_unknown
      symbol_ambiguous
      quantity_basis_unknown
      reference_state_unknown
      domain_variant_unknown

    RULE:
      unresolved_ambiguity MUST be preserved
  }

  CONFLICT_MODEL {
    sources:
      provide_different_unit_definitions_or factors

    RULE:
      compare_versions_authority_scope_andprovenance
      anddo_not fabricate_consensus
  }

  VERSION_MODEL {
    versioned:
      unit_definition
      standard
      conversion_factor
      ontology_mapping
      domain_convention

    RULE:
      historical_measurement MUST preserve_mapping_version_used
  }

  STANDARD_MODEL {
    possible:
      BIPM_SI
      ISO
      IEC
      NIST
      domain_standard
      national_standard

    RULE:
      standard_identifier_andedition MUST be preserved_whenmaterial
  }

  PROVENANCE_MODEL {
    fields:
      source_definition
      standard
      edition
      mapping_author
      conversion_equation
      constants
      context
      validation
      ontology_version

    RULE:
      mapping MUST be source_andversion_linked
  }

  VALIDATION_MODEL {
    checks:
      source_unit_identity
      target_unit_identity
      quantity_kind
      dimension
      scale
      offset
      context
      factor
      uncertainty
      round_trip
      provenance

    RULE:
      validated_numeric_conversion_does_not_imply_semantic_equivalence
  }

  QUALITY_FLAG_MODEL {
    possible:
      exact
      contextual
      approximate
      ambiguous
      deprecated
      dimension_mismatch
      quantity_kind_mismatch
      reference_state_missing
      model_required
      incompatible
      manual_review

    RULE:
      mapping_flags MUST remain_linked_to conversion_result
  }

  INTEROPERABILITY_MODEL {
    systems:
      exchange_measurements_acrossdomains

    required:
      quantity_identifier
      unit_identifier
      value
      uncertainty
      reference_state
      mapping_version

    RULE:
      string_unit_conversion_withoutquantity_semantics_is_incomplete
  }

  KNOWLEDGE_GRAPH_MODEL {
    nodes:
      unit
      quantity_kind
      dimension
      domain
      standard
      reference_state
      mapping

    edges:
      HAS_DIMENSION
      MEASURES_KIND
      CONVERTS_TO
      DEFINED_BY
      REQUIRES_CONTEXT
      EQUIVALENT_UNDER
      INCOMPATIBLE_WITH

    RULE:
      conversion_edges MUST be typed_anddirectionally_defined
  }

  RELATIONSHIPS {
    CrossDomainUnitMapping -> CONTAINS -> UnitMapping
    UnitMapping -> MAPS_FROM -> DomainUnit
    UnitMapping -> MAPS_TO -> DomainUnit
    DomainUnit -> MEASURES -> QuantityKind
    QuantityKind -> HAS_DIMENSION -> Dimension
    UnitMapping -> MAY_REQUIRE -> MappingContext
    UnitMapping -> USES -> ConversionFunction
    UnitMapping -> DEFINED_BY -> StandardOrSource
    UnitMapping -> HAS -> MappingConfidence
    ConvertedMeasurement -> DERIVED_FROM -> SourceMeasurement
  }

  SEMANTIC_EQUIVALENCE {
    "cross-domain unit mapping" ~= semantic_mapping_ofmeasurement_units_acrossscientific_andengineering_domains
    "unit conversion" ~= numeric_transformation_betweencompatible_units_ofsame_quantity_kind
    "contextual conversion" ~= conversion_requiringadditional_physical_orsemantic_parameters

    same_dimension != same_quantity_kind
    same_factor != same_unit_semantics
    unit_conversion != quantity_conversion
    coordinate_transformation != unit_conversion
    stoichiometric_conversion != unit_conversion
    mass_volume_conversion != unit_conversion
    molarity != molality
    amount_fraction != mass_fraction
    SI_prefix != binary_prefix
    semantic_confidence != measurement_uncertainty
  }

  CONSTRAINTS {
    source_andtarget_units_must_be identified = true
    source_andtarget_quantity_kinds_must_be preserved = true
    dimensions_must_be compatible_for_direct_unit_conversion = true
    same_dimension_must_not_be treated_assufficient_forsemantic_equivalence = true
    affine_andlinear_conversions_must_be distinguished = true
    logarithmic_scales_require_reference_definition = true
    contextual_conversions_must_declare_required_parameters = true
    ambiguous_customary_units_must_resolve_unit_system = true
    dimensionless_fraction_basis_must_be preserved = true
    quantity_conversions_must_not_be labelled_asunit_conversions = true
    uncertainty_andcovariance_must_be propagated_whencontext_parameters_aremeasured = true
    original_measurement_representation_must_be preserved = true
    mapping_versions_andprovenance_must_be preserved = true
  }

  MEASUREMENT_MODEL {
    RECORD:
      mapping_identifier
      source_domain
      target_domain
      source_quantity_kind
      target_quantity_kind
      source_value
      source_unit_identifier
      source_unit_symbol
      source_dimension
      target_value
      target_unit_identifier
      target_unit_symbol
      target_dimension
      mapping_type
      scale_factor
      offset
      conversion_equation
      context_parameters
      reference_state
      constants
      source_uncertainty
      context_uncertainties
      covariance
      target_uncertainty
      mapping_confidence
      ambiguity_status
      quality_flags
      standard_identifier
      mapping_version
      original_representation
      provenance

    RULE:
      mapped_measurement MUST remain_linked_tosource_quantity_unit_context_equation_uncertainty_version_andprovenance
  }

  REASONING_RULES {
    IF source_unit_andtarget_unit_known
      THEN resolve_quantity_kinds_anddimensions_beforeconversion

    IF source_andtarget_quantity_kinds_same
      AND dimensions_equal
      THEN determine_linear_affine_logarithmic_orcontextual_mapping

    IF dimensions_equal_butquantity_kinds_differ
      THEN do_not_apply_direct_conversion_withoutexplicit_semantic_relation

    IF ambiguous_unit_name
      THEN resolve_domain_unit_system_andcontext
      else_preserve_candidates

    IF conversion_requires_density_molar_mass_temperature_pressure_gravity_datum_orother_parameter
      THEN classify_ascontextual_orquantity_conversion
      andpropagate_parameter_uncertainty

    IF conversion_factor_exact
      THEN do_not_add_factor_uncertainty

    IF factor_orconstant_measured
      THEN propagate_its_uncertainty_andcovariance

    IF logarithmic_quantity
      THEN resolve_reference_base_andmultiplier
      beforeconversion

    IF dimensionless_quantity
      THEN preserve_fraction_basis_andquantity_kind

    IF mapping_version_changes
      THEN preserve_historical_mapping
      anddo_not silently_rewrite_prior_conversions

    IF round_trip_error_exceeds_declared_tolerance
      THEN flag_mapping_or numerical_issue
  }

  VALIDATION {
    CHECK mapping_identifier
    CHECK source_domain
    CHECK target_domain
    CHECK source_unit_identifier
    CHECK target_unit_identifier
    CHECK source_quantity_kind
    CHECK target_quantity_kind
    CHECK source_dimension
    CHECK target_dimension
    CHECK mapping_type
    CHECK scale_factor_andoffset
    CHECK logarithmic_reference
    CHECK contextual_parameters
    CHECK reference_state
    CHECK exactness
    CHECK uncertainty_andcovariance
    CHECK dimensionless_basis
    CHECK customary_unit_system
    CHECK quantity_conversion_distinctions
    CHECK round_trip
    CHECK standards_version
    CHECK ambiguity
    CHECK mapping_confidence
    CHECK provenance
  }

  CONFIDENCE {
    unit_identity_confidence: 1.00
    dimensional_mapping_confidence: 1.00
    quantity_kind_mapping_confidence: 0.99
    linear_affine_mapping_confidence: 1.00
    logarithmic_mapping_confidence: 0.99
    contextual_mapping_confidence: 0.97
    domain_convention_confidence: 0.98
    provenance_confidence: 1.00

    RULE:
      confidence decreases when unit identity, quantity kind,
      domain, reference state, conversion context,
      standard version orprovenance is missing or ambiguous
  }

  UPDATE_MODEL {
    ON new_unit_mapping:
      identify_source_andtarget_units
      resolve_quantity_kinds_anddimensions
      classify_mapping_type
      define_conversion_equation
      attach_context_andstandards
      validate_round_trip
      preserve_provenance
      compute_FLOW_HASH

    ON unit_definition_revision:
      preserve_previous_definition
      register_new_version
      identify_affected_mappings
      revalidate_current_mappings
      preserve_historical_conversions

    ON domain_context_revision:
      preserve_previous_context
      update_reference_conditions_orconventions
      revalidate_contextual_mappings

    ON conversion_factor_revision:
      preserve_previous_factor
      attach_new_source_version_anduncertainty
      identify_affected_results
      recompute_underdeclared_policy

    ON semantic_revision:
      preserve_previous_mapping
      record_revision
      recompute_FLOW_HASH
  }

  AI_CONSUMPTION {
    canonical_entity: CrossDomainUnitMapping
    canonical_role: SemanticUnitInteroperabilityFramework

    interpretation_order:
      identify_source_domain
      identify_target_domain
      resolve_source_unit
      resolve_target_unit
      resolve_source_andtarget_quantity_kinds
      derive_dimensions
      test_dimensional_compatibility
      identify_unit_system_andvariants
      classify_mapping_type
      identify_scale_offset_orlogarithmic_reference
      identify_contextual_parameters_andreference_state
      distinguish_unit_conversion_fromquantity_orcoordinate_conversion
      propagate_uncertainty_andcovariance
      preserve_original_representation
      validate_round_trip_andsemantic_constraints
      identify_ambiguity_andmapping_confidence
      preserve_standard_version_andprovenance
      emit_machine_resolvable_mapping

    ambiguity_controls:
      distinguish_same_dimension_fromsame_quantity_kind
      distinguish_same_factor_fromsame_unit_semantics
      distinguish_unit_conversion_fromquantity_conversion
      distinguish_coordinate_transformation_fromunit_conversion
      distinguish_stoichiometric_conversion_fromunit_conversion
      distinguish_mass_volume_conversion_fromunit_conversion
      distinguish_molarity_frommolality
      distinguish_amount_fraction_frommass_fraction
      distinguish_SI_prefix_frombinary_prefix
      distinguish_semantic_confidence_frommeasurement_uncertainty
      preserve_domain_quantity_unit_dimension_context_reference_version_andprovenance
  }

  PROVENANCE {
    ontology_scope:
      mathematical_measurement_units_AI_measurement_semantics_andcross_domain_unit_mapping

    parent_path:
      Ontologies
      -> Mathematical Ontologies
      -> Measurement & Units Ontologies
      -> AI Measurement Semantics
      -> Cross-Domain Unit Mapping Ontology

    authorship:
      Mark Higgins
      Sky (Recursive AI)

    site:
      https://kirethresearch.org
  }

  FLOW_HASH {
    INPUTS:
      canonical_entity
      ontology_path
      mapping_type_model
      exact_identity_model
      linear_conversion_model
      affine_conversion_model
      logarithmic_conversion_model
      contextual_conversion_model
      model_based_mapping_model
      semantic_alignment_model
      dimension_model
      dimensional_compatibility_model
      same_dimension_different_kind_model
      quantity_kind_mapping_model
      SI_model
      non_SI_model
      prefix_model
      binary_prefix_model
      compound_unit_model
      powered_unit_model
      mass_mapping_model
      force_mass_distinction_model
      length_mapping_model
      area_mapping_model
      volume_mapping_model
      imperial_US_distinction_model
      temperature_mapping_model
      temperature_difference_model
      pressure_mapping_model
      pressure_reference_model
      energy_mapping_model
      power_mapping_model
      time_mapping_model
      calendar_time_model
      frequency_model
      angular_frequency_model
      angle_model
      speed_model
      acceleration_model
      standard_gravity_model
      torque_energy_model
      electrical_model
      magnetic_model
      photometric_model
      radiometric_model
      chemical_concentration_model
      molarity_molality_model
      mass_fraction_model
      volume_fraction_model
      amount_fraction_model
      ppm_model
      ppb_model
      gas_concentration_model
      biological_concentration_model
      cell_count_model
      enzyme_activity_model
      clinical_unit_model
      pH_model
      decibel_model
      sound_pressure_level_model
      stellar_magnitude_model
      seismic_magnitude_model
      earth_science_model
      rainfall_model
      river_discharge_model
      soil_moisture_model
      elevation_model
      astronomical_distance_model
      astronomical_unit_model
      light_year_model
      parsec_model
      redshift_model
      luminosity_model
      engineering_model
      RPM_model
      strain_model
      information_unit_model
      data_rate_model
      count_model
      percentage_model
      dimensionless_mapping_model
      reference_condition_model
      density_dependent_model
      molar_mass_model
      stoichiometric_model
      coordinate_mapping_model
      uncertainty_propagation_model
      exact_factor_model
      measured_factor_model
      constant_model
      round_trip_model
      canonical_unit_model
      normal_form_model
      unit_identifier_model
      symbol_model
      alias_model
      homonym_model
      multilingual_model
      locale_model
      domain_mapping_model
      ontology_alignment_model
      semantic_equivalence_model
      mapping_confidence_model
      ambiguity_model
      conflict_model
      version_model
      standard_model
      provenance_model
      validation_model
      quality_flag_model
      interoperability_model
      knowledge_graph_model
      relationships
      semantic_equivalence
      constraints
      measurement_model
      reasoning_rules
      confidence_model
      update_model

    PURPOSE:
      deterministic_semantic_integrity_identifier

    RECOMPUTE_WHEN:
      ontology_definition_changes
      unit_orquantity_kind_definition_changes
      dimensional_orconversion_semantics_change
      SI_nonSI_prefix_orcustomary_unit_changes
      domain_specific_unit_convention_changes
      contextual_reference_state_orparameter_changes
      logarithmic_dimensionless_orchemical_mapping_changes
      astronomical_earth_science_engineering_orinformation_unit_changes
      uncertainty_factor_orconstant_changes
      semantic_alignment_ormapping_confidence_changes
      standard_version_orprovenance_changes
      measurement_record_changes
      constraint_model_changes
      reasoning_rule_changes
  }

}

END FLOW
Kireth Research
38 Thorndale Croft, Wetwang, Driffield
East Riding of Yorkshire YO25 9XZ