[lgoettgens]

Replace 40 checks of the form x = 0*x, x <> 0*x or x = 0*y in the library by IsZero( x ).

IsZero is shorter and avoids building a zero object just for the comparison. Its generic method does the same elm = 0*elm comparison, and some representations have faster methods.

🤖 Created with the help of Claude Code (Opus 5.5)

[james-d-mitchell]

Looks like a good change to me

[fingolfin]

CI fails, strange:

  testing: ~/work/gap/gap/tst/testinstall/meataxe.tst
  ########> Diff in ~/work/gap/gap/tst/testinstall/meataxe.tst:353
  # Input is:
  Length( MTX.BasisModuleHomomorphisms( M, M2 ) );
  # Expected output:
  4
  # But found:
  Error, Record Element: '<rec>.basisVectors' must have an assigned va\
  lue
  ########
      3263 ms (710 ms GC) and 459MB allocated for meataxe.tst

[james-d-mitchell]

I've seen this recently in the ci for Semigroups also, which I think is unrelated to the changes in this pr. I'll try to post the link when I'm back at my computer

[james-d-mitchell]

I've seen this recently in the ci for Semigroups also, which I think is unrelated to the changes in this pr. I'll try to post the link when I'm back at my computer

So, here's the related failure in the Semigroups CI:

https://github.com/semigroups/Semigroups/actions/runs/37783273881/job/113331490255?pr=1235

from

semigroups/Semigroups#1235

The error is identical to the one @fingolfin reported here.