Strange bug connected to GAP as a backend

[Peter Mueller]

Start with

g = SymmetricGroup(3)
chi = g.trivial_character()
u = g.subgroup([])

Next

reg = u.trivial_character().induct(g)
print(chi.scalar_product(reg))

yields as expected the answer 1.

Now repeat the very same two lines, but before doing so compute the  representatives of conjugacy classes of subgroups:

lg = g.conjugacy_classes_subgroups()
reg = u.trivial_character().induct(g)
print(chi.scalar_product(reg))

This results in

---------------------------------------------------------------------------

GAPError                                  Traceback (most recent call last)
[...]
GAPError: Error, no method found! Error, no 1st choice method found for `=' on 2 arguments

I omit the full traceback, because it is very well reproducible in versions 9.7 and 9.8.beta3, and also on the SageCell.

-- Peter Müller