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semifp: really ignore whitespace in ParseRelations #1189

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Merged
james-d-mitchell merged 1 commit into from
May 19, 2026
Merged

semifp: really ignore whitespace in ParseRelations #1189

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2 changes: 1 addition & 1 deletion gap/semigroups/semifp.gi
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Original file line number Diff line number Diff line change
Expand Up @@ -1102,7 +1102,7 @@ function(gens, inputstring)
fi;
od;

newinputstring := Filtered(inputstring, x -> x <> ' ');
newinputstring := Filtered(inputstring, x -> not x in " \r\t\n");
chars := List(gens, x -> String(x)[1]);
if PositionSublist(newinputstring, "=1") <> fail then
Add(chars, '1');
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14 changes: 14 additions & 0 deletions tst/standard/semigroups/semifp.tst
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Expand Up @@ -2670,6 +2670,20 @@ true
gap> IsSubsemigroupOfFpMonoid(Range(map));
true

# ParseRelations really ignore all whitespace
gap> F := FreeMonoid("a", "b", "c", "e");;
gap> R := ParseRelations(GeneratorsOfMonoid(F),
> """aa=1, bb=1, cc=1, (ab)^3=1, (bc)^3=1, (ca)^3=1, (abac)^2=1,
> (bcba)^2=1, (cacb)^2=1, ee=e, eaea=aeae, aeab=baea, beba=abeb,
> aeac=caea, ceca=acec, aeaea=aeae""");
[ [ a^2, <identity ...> ], [ b^2, <identity ...> ], [ c^2, <identity ...> ],
[ (a*b)^3, <identity ...> ], [ (b*c)^3, <identity ...> ],
[ (c*a)^3, <identity ...> ], [ (a*b*a*c)^2, <identity ...> ],
[ (b*c*b*a)^2, <identity ...> ], [ (c*a*c*b)^2, <identity ...> ],
[ e^2, e ], [ (e*a)^2, (a*e)^2 ], [ a*e*a*b, b*a*e*a ],
[ b*e*b*a, a*b*e*b ], [ a*e*a*c, c*a*e*a ], [ c*e*c*a, a*c*e*c ],
[ (a*e)^2*a, (a*e)^2 ] ]

# Unbind local variables, auto-generated by etc/tst-unbind-local-vars.py
gap> Unbind(BruteForceInverseCheck);
gap> Unbind(BruteForceIsoCheck);
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