At this stage, the not equal comparison fails:

sage: M = Manifold(4, 'M')
sage: X.<x,y,z,t> = M.chart()
sage: Form0 = M.mixed_form(comp=([0,0,0,0,0]))
sage: Form1 = M.mixed_form(comp=([1,0,0,0,0]))
sage: Form0 != Form1
False

(reported at https://ask.sagemath.org/question/52409/why-doesnt-or-work-for-mixed-forms/)

I already spotted the error: originally, richcmp is checked separately on each component and returns False if the check fails for at least one element. But for the inequality, it is enough when the check succeeds for at least one element because then both mixed forms are already unequal.

This bug gets fixed in this ticket. Furthermore, an equality check between mixed forms and differential forms will be possible.

CC: @egourgoulhon @tscrim @fchapoton @mkoeppe

Component: manifolds

Keywords: mixed_forms

Author: Michael Jung

Branch/Commit: 6f0f537

Reviewer: Eric Gourgoulhon

Issue created by migration from https://trac.sagemath.org/ticket/30108