From 0947fba33d80ae761ab031b8946f6b182ec093e0 Mon Sep 17 00:00:00 2001
From: joe-dw <josephdward@hotmail.co.uk>
Date: Fri, 19 Jun 2026 10:24:26 +0100
Subject: [PATCH] Fixed error with MinimalHereditarySubsetsVertex taking a
 semigroup instead of a digraph

---
 gap/congruences/congsemigraph.gd | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gap/congruences/congsemigraph.gd b/gap/congruences/congsemigraph.gd
index b665d5e10..bdaaa081c 100644
--- a/gap/congruences/congsemigraph.gd
+++ b/gap/congruences/congsemigraph.gd
@@ -23,6 +23,6 @@ DeclareOperation("CongruenceByWangPair",
 DeclareOperation("AsCongruenceByWangPair", [IsSemigroupCongruence]);
 
 DeclareOperation("MinimalHereditarySubsetsVertex",
-                 [IsGraphInverseSemigroup, IsPosInt]);
+                 [IsDigraph, IsPosInt]);
 
 DeclareAttribute("GeneratingCongruencesOfLattice", IsGraphInverseSemigroup);