IrreducibleDifferences( tbl, chars1, chars2 )
IrreducibleDifferences( tbl, chars1, chars2, scprmat )
IrreducibleDifferences( tbl, chars, "triangle" )
IrreducibleDifferences( tbl, chars, "triangle", scprmat )
returns the list of irreducible characters which occur as difference of
two elements of chars (if "triangle" is specified) or of an element
of chars1 and an element of chars2; if scprmat is not specified it
will be computed (see MatScalarProducts), otherwise we must have
[
scprmat[i][j] = ScalarProduct( tbl, chars[i], chars[j] )
]
resp.
[
scprmat[i][j] = ScalarProduct( tbl, chars1[i], chars2[j] )
].
gap> t:= CharTable( "A5" );;
gap> chars:= Sublist( t.irreducibles, [ 2 .. 4 ] );;
gap> chars:= Set( Tensored( chars, chars ) );;
gap> IrreducibleDifferences( t, chars, "triangle" );
[ [ 3, -1, 0, -E(5)-E(5)^4, -E(5)^2-E(5)^3 ],
[ 3, -1, 0, -E(5)^2-E(5)^3, -E(5)-E(5)^4 ] ]
GAP 3.4.4