add is_atlas_character_table

docs/src/Groups/group_characters.md

@@ -133,6 +133,7 @@ conjugacy_classes(tbl::GAPGroupCharacterTable)
 decomposition_matrix
 identifier(tbl::GAPGroupCharacterTable)
 induced_cyclic(tbl::GAPGroupCharacterTable)
+is_atlas_character_table
 is_duplicate_table
 maxes
 names_of_fusion_sources

gap/OscarInterface/gap/OscarInterface.gi

@@ -140,3 +140,38 @@ Perform( Oscar._GAP_deserializations,
              [ JuliaToGAP( IsString, entry[1] ), "IsObject", "IsObject" ],
              Julia.GAP.WrapJuliaFunc( entry[2] ) );
          end );
+
+############################################################################
+
+# The following can be removed as soon as the CTblLib package provides it
+# (not yet in CTblLib v1.3.9).
+if not IsBound( IsAtlasCharacterTable ) then
+  DeclareProperty( "IsAtlasCharacterTable", IsNearlyCharacterTable );
+
+  InstallMethod( IsAtlasCharacterTable,
+    [ "IsOrdinaryTable" ],
+    tbl -> PositionSublist( InfoText( tbl ),
+                            "origin: ATLAS of finite groups" ) <> fail );
+
+  InstallMethod( IsAtlasCharacterTable,
+    [ "IsBrauerTable" ],
+    tbl -> IsAtlasCharacterTable( OrdinaryCharacterTable( tbl ) ) );
+
+  AddSet( CTblLib.SupportedAttributes, "IsAtlasCharacterTable" );
+
+  DatabaseAttributeAddX( CTblLib.Data.IdEnumerator, rec(
+    identifier:= "IsAtlasCharacterTable",
+    type:= "values",
+    name:= "IsAtlasCharacterTable",
+    neededAttributes:= [ "InfoText" ],
+    create:= function( attr, id )
+      local infotext;
+
+      infotext:= attr.idenumerator.attributes.InfoText;
+      return PositionSublist( infotext.attributeValue( infotext, id ),
+                              "origin: ATLAS of finite groups" ) <> fail;
+      end,
+  ) );
+
+  CTblLib.ExtendAttributeOfIdEnumeratorExt( "IsAtlasCharacterTable", true );
+fi;

src/GAP/wrappers.jl

@@ -164,6 +164,7 @@ GAP.@wrap IsAlmostSimpleGroup(x::Any)::Bool
 GAP.@wrap IsAlternatingForm(x::Any)::Bool
 GAP.@wrap IsAlternatingGroup(x::Any)::Bool
 GAP.@wrap IsAssocWord(x::Any)::Bool
+GAP.@wrap IsAtlasCharacterTable(x::GapObj)::Bool
 GAP.@wrap IsBiCoset(x::Any)::Bool
 GAP.@wrap IsBijective(x::Any)::Bool
 GAP.@wrap IsBool(x::Any)::Bool

src/Groups/group_characters.jl

@@ -441,6 +441,35 @@ function Base.hash(tbl::GAPGroupCharacterTable, h::UInt)
   end
 end
 
+"""
+    is_atlas_character_table(tbl::GAPGroupCharacterTable)
+
+Return whether `tbl` is either an ordinary character table
+that belongs to the ATLAS of Finite Groups [CCNPW85](@cite)
+or a Brauer table whose underlying ordinary table
+belongs to the ATLAS of Finite Groups.
+
+One application of this function is to restrict the search with
+[`all_character_table_names`](@ref) to ATLAS tables.
+
+# Examples
+```jldoctest
+julia> tbl = character_table("A5");
+
+julia> is_atlas_character_table(tbl)
+true
+
+julia> is_atlas_character_table(mod(tbl, 2))
+true
+
+julia> is_atlas_character_table(character_table("A4"))
+false
+```
+"""
+function is_atlas_character_table(tbl::GAPGroupCharacterTable)
+  return GAPWrap.IsAtlasCharacterTable(GapObj(tbl))
+end
+
 
 ##############################################################################
 #

src/Groups/libraries/libraries.jl

@@ -56,6 +56,7 @@ function __init_group_libraries()
 
   copy!(_ctbl_filter_attrs, _group_filter_attrs)
   _add_bool_attr(_ctbl_filter_attrs, is_duplicate_table, GAP.Globals.IsDuplicateTable)
+  _add_bool_attr(_ctbl_filter_attrs, is_atlas_character_table, GAP.Globals.IsAtlasCharacterTable)
 
   empty!(_atlas_group_filter_attrs)
   _atlas_group_filter_attrs[degree] = (_IntOrIntVec, GAP.Globals.NrMovedPoints, nothing)

src/exports.jl

@@ -804,6 +804,7 @@ export is_almost_simple, has_is_almost_simple, set_is_almost_simple
 export is_alternating
 export is_ample
 export is_archimedean_solid
+export is_atlas_character_table
 export is_ball
 export is_basepoint_free
 export is_bicoset

test/Groups/libraries.jl

@@ -284,6 +284,12 @@ end
    @test order(H) == 720
 end
 
+@testset "Library of character tables" begin
+   l1 = all_character_table_names(is_atlas_character_table, !is_duplicate_table)
+   l2 = all_character_table_names(is_atlas_character_table)
+   @test l1 == l2
+end
+
 @testset "Groups with few conjugacy classes" begin
    @testset for n in 1:14
       @test has_groups_with_class_number(n)