diff --git a/example.ttl b/example.ttl
deleted file mode 100644
index b01c3a574ebf9c7130d69cc27fc0271965783e44..0000000000000000000000000000000000000000
--- a/example.ttl
+++ /dev/null
@@ -1,451 +0,0 @@
-# baseURI: https://unl.tetras-libre.fr/rdf/example
-# imports: http://www.w3.org/2008/05/skos-xl
-# imports: http://www.w3.org/ns/shacl#
-# imports: https://unl.tetras-libre.fr/rdf/schema
-
-@prefix : <https://unl.tetras-libre.fr/rdf/example#> .
-@prefix owl: <http://www.w3.org/2002/07/owl#> .
-@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
-@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
-@prefix sh: <http://www.w3.org/ns/shacl#> .
-@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
-@prefix unl: <https://unl.tetras-libre.fr/rdf/schema#> .
-@prefix xml: <http://www.w3.org/XML/1998/namespace> .
-@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
-
-rdf:Statement
-  rdf:type owl:Class ;
-.
-<https://unl.tetras-libre.fr/rdf/example>
-  rdf:type owl:Ontology ;
-  owl:imports <http://www.w3.org/2008/05/skos-xl> ;
-  owl:imports sh: ;
-  owl:imports <https://unl.tetras-libre.fr/rdf/schema> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#2>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "2" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#2__00000005> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#2__00000005>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "2" ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#2> ;
-  unl:is_substructure_of :R1 ;
-  unl:is_target_of :state_00000004__qua__2_00000005 ;
-.
-:R1
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UNL_Sentence ;
-  rdfs:label "The system allows a radio channel to take on two states: Listening and Traffic."@en ;
-  skos:altLabel """[S:R1]
-{org:en}
-The system allows a radio channel to take on two states: Listening and Traffic.
-{/org}
-{unl}
-aoj( allow(icl>be, aoj>thing, ben>thing, obj>uw, equ>make_possible).@entry, system(icl>group).@def )
-obj( allow(icl>be, aoj>thing, ben>thing, obj>uw, equ>make_possible).@entry, take_on(aoj>thing, equ>assume,icl>change, obj>thing) )
-ben( allow(icl>be, aoj>thing, ben>thing, obj>uw, equ>make_possible).@entry, channel(icl>radiowave).@indef)
-aoj( take_on(aoj>thing, equ>assume, icl>change, obj>thing), channel(icl>radiowave).@indef ) 
-obj( take_on(aoj>thing, equ>assume, icl>change, obj>thing), state(icl>attribute).@plu )   
-qua( state(icl>attribute).@plu, 2 )   
-cnt( state(icl>attribute).@plu, listening(icl>sensing) )
-and( listening(icl>sensing),traffic(icl>communication) )
-{/unl}
-[/S]"""@unl ;
-  unl:is_substructure_of :Test_requirements_SEM2020 ;
-.
-:R2
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UNL_Sentence ;
-  rdfs:label "The system displays a channel in green when it is in broadcast state"@en ;
-  skos:altLabel """[S:R2]
-{org:en}
-The system displays a channel in green when it is in broadcast state 
-{/org}
-{unl}
-agt(display(icl>show,equ>exhibit,agt>thing,obj>thing).@entry.@present,system(icl>group).@def)
-mod(channel(icl>radiowave).@indef,green(icl>adj,iof>color))
-obj(display(icl>show,equ>exhibit,agt>thing,obj>thing).@entry.@present,channel(icl>radiowave).@indef)
-tim(display(icl>show,equ>exhibit,agt>thing,obj>thing).@entry.@present,when(icl>how,com>always,tim<uw,obj>uw))
-aoj:01(be_in_a_state(aoj>thing,icl>be,obj>state).@entry.@present,channel(icl>radiowave).@indef)
-plc:01(state(icl>attribute),broadcast(icl>message))
-obj:01(be_in_a_state(aoj>thing,icl>be,obj>state).@entry.@present,state(icl>attribute))
-obj(when(icl>how,com>always,tim<uw,obj>uw),:01)
-{/unl}
-[/S]""" ;
-  unl:is_substructure_of :Test_requirements_SEM2020 ;
-.
-:Test_UW_Volume
-  rdf:type owl:Class ;
-  rdf:Type owl:Class ;
-  rdfs:subClassOf unl:UW_Lexeme ;
-.
-:Test_requirements_SEM2020
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UNL_Document ;
-  unl:is_superstructure_of :R1 ;
-  unl:is_superstructure_of :R2 ;
-.
-:UNL_Scope_00000017
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UNL_Scope ;
-  rdfs:label "01"@fr ;
-  unl:is_substructure_of :R2 ;
-.
-<https://unl.tetras-libre.fr/rdf/example#allow(icl--be,aoj--thing,ben--thing,obj--uw,equ--make_possible)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "allow(icl>be, aoj>thing, ben>thing, obj>uw, equ>make_possible)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#allow(icl--be,aoj--thing,ben--thing,obj--uw,equ--make_possible)__00000000> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#allow(icl--be,aoj--thing,ben--thing,obj--uw,equ--make_possible)__00000000>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "allow(icl>be, aoj>thing, ben>thing, obj>uw, equ>make_possible)" ;
-  unl:aoj <https://unl.tetras-libre.fr/rdf/example#system(icl--group)__00000001> ;
-  unl:ben <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000003> ;
-  unl:has_attribute "@entry"^^unl:att ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#allow(icl--be,aoj--thing,ben--thing,obj--uw,equ--make_possible)> ;
-  unl:is_source_of :allow_00000000__aoj__system_00000001 ;
-  unl:is_source_of :allow_00000000__ben__channel_00000003 ;
-  unl:is_source_of :allow_00000000__obj__take_on00000002 ;
-  unl:is_substructure_of :R1 ;
-  unl:obj <https://unl.tetras-libre.fr/rdf/example#take_on(aoj--thing,equ--assume,icl--change,obj--thing)__00000002> ;
-.
-:allow_00000000__aoj__system_00000001
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:aoj ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#allow(icl--be,aoj--thing,ben--thing,obj--uw,equ--make_possible)__00000000> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#system(icl--group)__00000001> ;
-.
-:allow_00000000__ben__channel_00000003
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:ben ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#allow(icl--be,aoj--thing,ben--thing,obj--uw,equ--make_possible)__00000000> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000003> ;
-.
-:allow_00000000__obj__take_on00000002
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:obj ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#allow(icl--be,aoj--thing,ben--thing,obj--uw,equ--make_possible)__00000000> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#take_on(aoj--thing,equ--assume,icl--change,obj--thing)__00000002> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#be_in_a_state(aoj--thing,icl--be,obj--state)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "be_in_a_state(aoj>thing,icl>be,obj>state)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#be_in_a_state(aoj--thing,icl--be,obj--state)__00000013> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#be_in_a_state(aoj--thing,icl--be,obj--state)__00000013>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "be_in_a_state(aoj>thing,icl>be,obj>state)" ;
-  unl:aoj <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000014> ;
-  unl:has_attribute "@entry"^^unl:att ;
-  unl:has_attribute "@present"^^unl:att ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#be_in_a_state(aoj--thing,icl--be,obj--state)> ;
-  unl:is_source_of :be_in_a_state_00000013__aoj__channel_00000014 ;
-  unl:is_source_of :be_in_a_state_00000013__obj__state_00000015 ;
-  unl:is_substructure_of :R2 ;
-  unl:obj <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000015> ;
-.
-:be_in_a_state_00000013__aoj__channel_00000014
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:aoj ;
-  unl:has_scope :UNL_Scope_00000017 ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#be_in_a_state(aoj--thing,icl--be,obj--state)__00000013> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000014> ;
-.
-:be_in_a_state_00000013__obj__state_00000015
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:obj ;
-  unl:has_scope :UNL_Scope_00000017 ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#be_in_a_state(aoj--thing,icl--be,obj--state)__00000013> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000015> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#broadcast(icl--message)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "broadcast(icl>message)" ;
-  unl:has_id "202004223698" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#broadcast(icl--message)__00000016> ;
-  unl:icl <https://unl.tetras-libre.fr/rdf/example#message(icl--thing)> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#broadcast(icl--message)__00000016>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "broadcast(icl>message)" ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#broadcast(icl--message)> ;
-  unl:is_substructure_of :R2 ;
-  unl:is_target_of :state_00000015__mod__broadcast_00000016 ;
-.
-<https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "channel(icl>radiowave)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000003> ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000014> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000003>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "channel(icl>radiowave)" ;
-  unl:has_attribute "@indef"^^unl:att ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)> ;
-  unl:is_substructure_of :R1 ;
-  unl:is_target_of :allow_00000000__ben__channel_00000003 ;
-  unl:is_target_of :take_on__00000002_aoj__channel_00000003 ;
-.
-<https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000014>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "channel(icl>radiowave)" ;
-  unl:has_attribute "@indef"^^unl:att ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)> ;
-  unl:is_substructure_of :R2 ;
-  unl:is_target_of :be_in_a_state_00000013__aoj__channel_00000014 ;
-.
-<https://unl.tetras-libre.fr/rdf/example#green(icl--adj,iof--color)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "green(icl>adj,iof>color)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#green(icl--adj,iof--color)__00000011> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#green(icl--adj,iof--color)__00000011>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "green(icl>adj,iof>color)" ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#green(icl--adj,iof--color)> ;
-  unl:is_substructure_of :R2 ;
-  unl:is_target_of :channel_00000014__plc__green_00000011 ;
-.
-<https://unl.tetras-libre.fr/rdf/example#light(icl--thing)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "light(icl>thing)" ;
-.
-<https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000014>
-  unl:is_source_of :channel_00000014__plc__green_00000011 ;
-  unl:is_target_of :display_00000008__obj__channel_00000014 ;
-  unl:plc <https://unl.tetras-libre.fr/rdf/example#green(icl--adj,iof--color)__00000011> ;
-.
-:channel_00000014__plc__green_00000011
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:plc ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000014> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#green(icl--adj,iof--color)__00000011> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#listening(icl--sensing)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "listening(icl>sensing)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#listening(icl--sensing)__00000006> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#listening(icl--sensing)__00000006>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "listening(icl>sensing)" ;
-  unl:and <https://unl.tetras-libre.fr/rdf/example#traffic(icl--communication)__00000007> ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#listening(icl--sensing)> ;
-  unl:is_source_of :listening_00000006__and__traffic_00000007 ;
-  unl:is_substructure_of :R1 ;
-  unl:is_target_of :state_00000004__cnt__listening_00000006 ;
-.
-:listening_00000006__and__traffic_00000007
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:and ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#listening(icl--sensing)__00000006> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#traffic(icl--communication)__00000007> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#message(icl--thing)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "message(icl>thing)" ;
-.
-:occurences_to_tmpLexemes
-  rdf:type sh:SPARQLRule ;
-  sh:construct """PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> 
-PREFIX unl: <https://unl.tetras-libre.fr/rdf/schema#>
-CONSTRUCT {
-?dic rdfs:subClassOf unl:UW_Lexeme .
-?lex a ?dic ; rdfs:label ?occLabel ; unl:has_occurrence ?this.
-?this unl:is_occurrence_of ?lex .
-}
-WHERE {
-?doc a unl:UNL_Document .
-?this a unl:UW_Occurrence ; unl:is_unl_substructure_of+ ?doc .
-?this rdfs:label ?occLabel .
-BIND (uri(concat('https://unl.tetras-libre.fr/rdf/example#',replace(replace(?occLabel,' ',''),'>','--'))) AS ?lex)
-BIND (uri(concat(str(?doc),'_tmpDictionary')) AS ?dic)
-}	""" ;
-.
-<https://unl.tetras-libre.fr/rdf/example#display(icl--show,agt--thing,obj--thing,equ--exhibit)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "display(icl>show,agt>thing,obj>thing,equ>exhibit)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#display(icl--show,agt--thing,obj--thing,equ--exhibit)__00000008> ;
-.
-
-<https://unl.tetras-libre.fr/rdf/example#display(icl--show,agt--thing,obj--thing,equ--exhibit)__00000008>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "display(icl>show,agt>thing,obj>thing,equ>exhibit)" ;
-  unl:agt <https://unl.tetras-libre.fr/rdf/example#system(icl--group)__00000009> ;
-  unl:has_attribute "@entry"^^unl:att ;
-  unl:has_attribute "@present"^^unl:att ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#display(icl--show,agt--thing,obj--thing,equ--exhibit)> ;
-  unl:is_source_of :display_00000008__agt__system_00000009 ;
-  unl:is_source_of :display_00000008__obj__channel_00000014 ;
-  unl:is_source_of :display_00000008__tim__when_00000012 ;
-  unl:is_substructure_of :R2 ;
-  unl:obj <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000014> ;
-  unl:tim <https://unl.tetras-libre.fr/rdf/example#when(icl--how,com--always,tim--uw,obj--uw)__00000012> ;
-.
-:display_00000008__agt__system_00000009
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:agt ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#display(icl--show,agt--thing,obj--thing,equ--exhibit)__00000008> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#system(icl--group)__00000009> ;
-.
-:display_00000008__obj__channel_00000014
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:obj ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#display(icl--show,agt--thing,obj--thing,equ--exhibit)__00000008> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000014> ;
-.
-:display_00000008__tim__when_00000012
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:tim ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#display(icl-show,agt--thing,obj--thing,equ--exhibit)__00000008> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#when(icl--how,com--always,tim--uw,obj--uw)__00000012> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "state(icl>attribute)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000004> ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000015> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000004>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "state(icl>attribute)" ;
-  unl:cnt <https://unl.tetras-libre.fr/rdf/example#listening(icl--sensing)__00000006> ;
-  unl:has_attribute "@plu"^^unl:att ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)> ;
-  unl:is_source_of :state_00000004__cnt__listening_00000006 ;
-  unl:is_source_of :state_00000004__qua__2_00000005 ;
-  unl:is_substructure_of :R1 ;
-  unl:is_target_of :take_on_00000002__obj__state_00000004 ;
-  unl:qua <https://unl.tetras-libre.fr/rdf/example#2__00000005> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000015>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "state(icl>attribute)" ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)> ;
-  unl:is_source_of :state_00000015__mod__broadcast_00000016 ;
-  unl:is_substructure_of :R2 ;
-  unl:is_target_of :be_in_a_state_00000013__obj__state_00000015 ;
-  unl:mod <https://unl.tetras-libre.fr/rdf/example#broadcast(icl--message)__00000016> ;
-.
-:state_00000004__cnt__listening_00000006
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:cnt ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000004> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#listening(icl--sensing)__00000006> ;
-.
-:state_00000004__qua__2_00000005
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:qua ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000004> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#2__00000005> ;
-.
-:state_00000015__mod__broadcast_00000016
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:mod ;
-  unl:has_scope :UNL_Scope_00000017 ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000015> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#broadcast(icl--message)__00000016> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#system(icl--group)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "system(icl>group)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#system(icl--group)__00000001> ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#system(icl--group)__00000009> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#system(icl--group)__00000001>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "system(icl>group)" ;
-  unl:has_attribute "@def"^^unl:att ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#system(icl--group)> ;
-  unl:is_substructure_of :R1 ;
-  unl:is_target_of :allow_00000000__aoj__system_00000001 ;
-.
-<https://unl.tetras-libre.fr/rdf/example#system(icl--group)__00000009>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "system(icl>group)" ;
-  unl:has_attribute "@def"^^unl:att ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#system(icl--group)> ;
-  unl:is_substructure_of :R2 ;
-  unl:is_target_of :display_00000008__agt__system_00000009 ;
-.
-<https://unl.tetras-libre.fr/rdf/example#take_on(aoj--thing,equ--assume,icl--change,obj--thing)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "take_on(aoj>thing, equ>assume,icl>change, obj>thing)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#take_on(aoj--thing,equ--assume,icl--change,obj--thing)__00000002> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#take_on(aoj--thing,equ--assume,icl--change,obj--thing)__00000002>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "take_on(aoj>thing, equ>assume,icl>change, obj>thing)" ;
-  unl:aoj <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000003> ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#take_on(aoj--thing,equ--assume,icl--change,obj--thing)> ;
-  unl:is_source_of :take_on_00000002__obj__state_00000004 ;
-  unl:is_source_of :take_on__00000002_aoj__channel_00000003 ;
-  unl:is_substructure_of :R1 ;
-  unl:is_target_of :allow_00000000__obj__take_on00000002 ;
-  unl:obj <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000004> ;
-.
-:take_on_00000002__obj__state_00000004
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:obj ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#take_on(aoj--thing,equ--assume,icl--change,obj--thing)__00000002> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#state(icl--attribute)__00000004> ;
-.
-:take_on__00000002_aoj__channel_00000003
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:aoj ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#take_on(aoj--thing,equ--assume,icl--change,obj--thing)__00000002> ;
-  unl:has_target <https://unl.tetras-libre.fr/rdf/example#channel(icl--radiowave)__00000003> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#traffic(icl--communication)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "traffic(icl>communication)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#traffic(icl--communication)__00000007> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#traffic(icl--communication)__00000007>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "traffic(icl>communication)" ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#traffic(icl--communication)> ;
-  unl:is_substructure_of :R1 ;
-  unl:is_target_of :listening_00000006__and__traffic_00000007 ;
-.
-<https://unl.tetras-libre.fr/rdf/example#when(icl--how,com--always,tim--uw,obj--uw)>
-  rdf:type :Test_UW_Volume ;
-  rdfs:label "when(icl>how,com>always,tim>uw,obj>uw)" ;
-  unl:has_occurrence <https://unl.tetras-libre.fr/rdf/example#when(icl--how,com--always,tim--uw,obj--uw)__00000012> ;
-.
-<https://unl.tetras-libre.fr/rdf/example#when(icl--how,com--always,tim--uw,obj--uw)__00000012>
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:UW_Occurrence ;
-  rdfs:label "when(icl>how,com>always,tim>uw,obj>uw)" ;
-  unl:is_occurrence_of <https://unl.tetras-libre.fr/rdf/example#when(icl--how,com--always,tim--uw,obj--uw)> ;
-  unl:is_substructure_of :R2 ;
-  unl:is_target_of :display_00000008__tim__when_00000012 ;
-  unl:obj :UNL_Scope_00000017 ;
-.
-:when_00000012__obj__Scope_00000017
-  rdf:type owl:NamedIndividual ;
-  rdf:type unl:obj ;
-  unl:has_source <https://unl.tetras-libre.fr/rdf/example#when(icl--how,com--always,tim--uw,obj--uw)__00000012> ;
-  unl:has_target :UNL_Scope_00000017 ;
-.
-unl:UW_Occurrence
-  rdf:type sh:NodeShape ;
-.
diff --git a/schema.ttl b/schema.ttl
index 142ffb7f43a852f29277d5cf7c5b0b94c32c04f6..662be0f1fdd866c00b4bf6add5641ec8361ae38d 100644
--- a/schema.ttl
+++ b/schema.ttl
@@ -2451,6 +2451,12 @@ train to NY = gol(train;NY)"""@en ;
   rdfs:domain :UNL_Structure ;
   rdfs:subPropertyOf :unlAnnotationProperty ;
 .
+:has_index
+  rdf:type owl:DatatypeProperty ;
+  rdfs:domain :UNL_Structure ;
+  rdfs:range xsd:integer ;
+  rdfs:subPropertyOf :unlDatatypeProperty ;
+.
 :has_master_definition
   rdf:type owl:AnnotationProperty ;
   rdfs:domain :UW_Lexeme ;