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Should a search for a term include its narrower terms?


FR Implementation defines which FRs are transitive: look for a loop at the last node (when there are 2 diagrams, look at the right one).
However, various defects were found (see Details) and the issue was reconsidered.
Now Transitive vs Non-transitive defines transitivity.

The Problem

Many FRs implement transitivity using the corresponding CRM relation: P88i_forms_part_of (place), P107i_is_current_or_former_member_of (person/organization, if applicable), P9i_forms_part_of (period), P127_has_broader_term (material/type in FR2).

BMX Issues#Thesaurus Requirements says: "if the thesaurus is hierarchical, use skos:broader and the appropriate CRM relation". Unfortunately many BM thesauri do not use CRM relations but only skos:broader. Although there is a specific task to ensure BM thesauri satisfy requirements, this has slipped BM's attention and Ontotext's QA (i.e. Vlado)

The Solution

Normally adding a rule requires reloading the repository, so that all facts from the new rule can be inferred. But in order to avoid reloading the BM data, we'll try this:

  • Define a generic rule for the Proton predicate ptop:transitiveOver (see FR Implementation#transitiveOver)
  • Restart OWLIM with the new rules
  • Load the new file FR-Transitive.ttl that declares certain FRs to be transitiveOver skos:broader, eg
    rso:FR2_has_type ptop:transitiveOver skos:broader.
  • Fingers crossed and stars in alignment, this should infer transitive closure over skos:broader.
    It may fail since we've marked our data using onto:systemTransaction (which basically means it's read-only), which may cut-off forward-chaining on Assert.
    But I hope onto:systemTransaction only cuts-off backward-chaining on Retract.

Mind the Direction

Dominic wrote in RS-1830

  • "Search for Rembrandt (created) and animal (is/has/about) finds no results. If you search for mammal (a narrower term of animal) finds results."

Search for a term never includes its broader terms.

  • For example, if you search for "Mammal", RS should find objects about pigs and horses.
    However, RS should not find animals that are not mammals (eg Fish).
    By the same token, RS should not find objects about "Animal"
  • So this page defines which FRs should find narrower terms, but no FR finds broader terms.

Note: using skos:broader in The Solution is correct: every narrow term contributes its objects to its broader term, but not vice versa.

Test Cases

  1. Created by "Rembrandt" and is/has/about "animal": should find some pigs and horses
  2. Met "Joseph Mallord William" and is/has/about "boat/ship": finds 231 in COL, only 7 in RS
  3. Created in "Tokyo-to" and is/has/about "vase": should find JCR5403 "Set of altar utensils" which includes a "temple-vase" (a subtype of "vase")
    Note: there are 12 subtypes of vase:
  4. present at "Ancient Egypt (Material Culture)": should find many objects, not just 4.
    I.e. it should use this hierarchy:
    • Ancient Egypt
      • Early Dynastic Egypt
        • 1st dynasty
        • 2nd dynasty ...
        • 26th Dynasty (eg GAA86605)
  5. Found at "Sofia-city" and made of "copper-alloy": should find EEU71607 "A fabric belt with metal buckle" (made of "brass" which is a subtype of "copper-alloy")
  6. Created by "Dutch (BM Nationality)": should find objects by "Rembrandt"

Transitive vs Non-transitive

The table below describes which FRs are transitive.

  • CRM and SKOS transitivity should be the same
  • UPPERCASE shows what we must add
FR property name range CRM SKOS Why
rso:FR12_found_by found by E39_Actor no no Nobody would search for "found by British"
rso:FR12_has_met met E39_Actor no no Nobody would search for "met British"
rso:FR15_influenced_by influenced by E39_Actor no no We don't have creator's school (eg Impressionism)
rso:FR51_former_or_current_owner_keeper all owners/keepers E39_Actor no no  
rso:FR52_current_owner_keeper owner/keeper E39_Actor no no  
rso:FR67_about_actor about E39_Actor no no Aboutness
rso:FR92i_created_by created/modified by E39_Actor P107i no BM thes defines Nationality, Profession with CRM sub-props not SKOS
rso:FR12_was_present_at present at E4_Period P9i,P10 ADD From Period
rso:FR67_about_period about E4_Period no no Aboutness
rso:FR7_from_place from E53_Place P89 no need Place FRs
rso:FR12_found_at found at E53_Place P89 no need Place FRs
rso:FR55_located_in located in E53_Place P89 no need Place FRs
rso:FR67_about_place about E53_Place no no Aboutness
rso:FR92i_created_in created in E53_Place P89 no need Place FRs
rso:FR2_has_type is/has/about E55_Type P127 ADD  
rso:FR45_is_made_of made of E57_Material ADD P127 ADD  
rso:FR32_used_technique used rso:E55_Technique ADD P127 ADD  



We decided that About Place should not be transitive: neither broader nor narrower

  • If it is about Knossos, is it also about Crete, Europe, the World, and the Milky Way?? NO
  • Is a picture of a lake in Europe (EPF112795) also about the village Banya in Bulgaria? NO
  • Is a photo representing Oceania (PPA361578) also about Polynesia, Easter Island and Rano Raraku? NO

By the same logic About Actor and About Period are not transitive

Place FRs

The Place FRs (Created, Located, Found, From; but not About) are transitve:

  • Any object related to a sub-place is also related to its super-places.
  • So if you search with a super-place, it will find objects related to all its sub-places


  • The FR rules use P89_falls_within
  • The BM Place thesaurus uses P88i_forms_part_of (in addition to skos:broader)
  • rso.ttl fixes an omission in ECRM:
    crm:P88i_forms_part_of rdfs:subPropertyOf crm:P89_falls_within. 

Person FRs

  • Actor: owner/keeper, influenced, met, about, found: NO; created YES
    • The choice that "found" is not transitive is a bit arbitrary and means you can't search "found by British".
      The other choices I believe are reasonable
    • I use P107i_is_current_or_former_member_of, so you can search "created by Dutch" and will find objects by Rembrandt.

Type, Subject

I have added "P127_has_broader_term" to search by Type (is/has/about), so a search with a broader term will return all narrower terms as well

Material, Technique

Made of Material and Used Technique should also be transitive

EEU71607 A fabric belt with metal buckle
The query "found at Sofia-city and made of copper-alloy" returns this object from BM search but does not return it in RS search, why?

  • The object is
  • It is found with "found at Sofia-city and made of brass".
  • the object rso:FR45_is_made_of thes:x10411, thes:x10646, thes:x11991
  • thes:x10411 (brass) has skos:broader thes:x10627 (copper alloy). (This last term has altLabel "brass" but scopeNote that explains that it's different from brass).
  • the current definition of FR45_is_made_of doesn't traverse the broader hierarchy.
  • the old definition of FR45_is_made_of doesn't traverse the broader hierarchy either.
  • in fact it has been defined like this since 15 May 2012
  • This came from Martin's definition: TR ICS-FORTH/TR-429 (April 2012) on p64 when defining "Thing is made of" does not use "P127 has broader term".
    • I now notice that one p63 when defining "Thing has type" they DO use "P127 has broader term" (so the above is a discrepancy)
  • It has survived supposed inspections by Dominic and Peter Main

Both the BM Material and BM Technique thesauri are hierarchical:

From Period

Material Culture is mapped to crm:E4_Period and skos:Concept, and object production is linked to the Period using P10_falls_within:

  crm:P3_has_note "Production Period / Culture :: Late Christian Period";
  crm:P10_falls_within thes:x14625 .

One can search for the period using FR12_was_present_at "Thing was present at (has met, is from) event/period" (see FR Enhancements#Thing present at Event or from Period and FR Implementation#Thing has met Event- FR12_was_present_at). There's a transitive loop over P9&P10 at the end, so it's transitive.

Unfortunately the Period thesaurus uses only skos:broader but not P9_consists_of, eg

thes:x107598 a crm:E4_Period, skos:Concept;
  skos:inScheme thes:matcult;
  skos:prefLabel "Ancient Egypt";
  skos:broader thes:x112519.
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