fix filter problem and also add test

semigroups · Jul 31, 2024 · 513712b · 513712b
1 parent 554e0dd
commit 513712b
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/gap/attributes/attr.gi b/gap/attributes/attr.gi
@@ -775,7 +775,7 @@ end);
 
 
 InstallMethod(InversesOfSemigroupElementNC,
-"for CanUseFroidurePin and a multiplicative element",
+"for a semigroup that can use froidure-pin and a multiplicative element",
 [CanUseFroidurePin, IsMultiplicativeElement],
 function(S, a)
   local R, L, inverses, e, f, s;
@@ -793,7 +793,7 @@ function(S, a)
 end);
 
 InstallMethod(InversesOfSemigroupElement,
-"for a semigroup and a multiplicative element",
+"for a semigroup that can use froidure-pin and a multiplicative element",
 [CanUseFroidurePin, IsMultiplicativeElement],  # to beat the library method
 function(S, x)
   if not IsFinite(S) then
@@ -834,7 +834,7 @@ function(S, a)
 end);
 
 InstallMethod(OneInverseOfSemigroupElement,
-"for CanUseFroidurePin and a multiplicative element",
+"for a semigroup and a multiplicative element",
 [IsSemigroup, IsMultiplicativeElement],
 function(S, x)
   if not IsFinite(S) then

diff --git a/tst/standard/attributes/attr.tst b/tst/standard/attributes/attr.tst
@@ -1494,6 +1494,11 @@ fail
 gap> OneInverseOfSemigroupElement(S, S.1 * S.2 * S.1);
 Matrix(IsBooleanMat, [[1, 1, 1], [1, 1, 1], [0, 0, 1]])
 
+# OneInverseOfSemigroupElement, for a semigrop that cannot use Froidure-PrincipalFactor
+gap> S := Semigroup(SEMIGROUPS.UniversalFakeOne);;
+gap> OneInverseOfSemigroupElement(S, S.1);
+[ <universal fake one> ]
+
 # OneInverseOfSemigroupElement, for an infinite semigroup, 1
 gap> S := FreeSemigroup(1);
 <free semigroup on the generators [ s1 ]>