WeylGroup.subgroup doesn't create a subset

[vit-tucek]

The following code

W = WeylGroup("A2", prefix="s")
s = W.simple_reflections()
H = W.subgroup([s[2]])
s[2] in list(H)

returns False. One workaround is s[2] in list(W(x) for x in H).

CC: @sagetrac-sage-combinat

Component: combinatorics

Reviewer: Travis Scrimshaw, Simon Brandhorst

Issue created by migration from https://trac.sagemath.org/ticket/24393

[vit-tucek]

comment:2

Seems like a duplicate of #19010

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:3

I agree that this is essentially a duplicate of #19010 as the root cause is the same:

sage: W.has_coerce_map_from(H)
False

Every subgroup should have a coercion into its ambient group.

[simonbrandhorst]

comment:4

indeed.

[simonbrandhorst]

Changed reviewer from Travis Scrimshaw to Travis Scrimshaw, Simon Brandhorst

[embray]

comment:6

Presuming these are all correctly reviewed as either duplicate, invalid, or wontfix.