Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

acting: add WeakInverse method for all types #936

Draft
wants to merge 1 commit into
base: main
Choose a base branch
from
Draft

acting: add WeakInverse method for all types #936

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
26 changes: 26 additions & 0 deletions gap/main/setup.gi
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1268,3 +1268,29 @@ InstallMethod(WeakInverse, "for a partial perm",

InstallMethod(WeakInverse, "for a bipartition",
[IsBipartition], Star);

InstallMethod(WeakInverse, "for a matrix over ff",
[IsMatrixObjOverFiniteField], RightInverse);

InstallMethod(WeakInverse, "for a McAlister triple semigroup element",
[IsMcAlisterTripleSemigroupElement], INV);

InstallMethod(WeakInverse, "for a Rees 0-matrix semigroup",
[IsReesZeroMatrixSemigroupElement],
function(x)
local R, mat, i, j, k, l;

R := ReesMatrixSemigroupOfFamily(FamilyObj(x));
if IsMultiplicativeZero(R, x) then
return x;
fi;

mat := Matrix(R);
i := x[1];
j := x[3];

k := First(Rows(R), k -> mat[j][k] <> 0);
l := First(Columns(R), l -> mat[l][i] <> 0);

return RMSElement(R, k, mat[j][k] ^ -1 * x[2] ^ -1 * mat[l][i] ^ -1, l);
end);