Test for Set equality    
   [ Note : as of 2023-12-24, my browser retrieves this question that seems t have never been asked, (an still of interest). So I pot it very lately... ]
Inspired by this question, I stumbled in an unexpected difficulty when trying to compare two Sets :
sage: L[:2]
[[
[ 2 -2]  [0 1]  [   0    1]
[-2  1], [0 1], [   0 -1/2]
],
 [
[ 2 -2]  [   0    1]  [0 1]
[-2  1], [   0 -1/2], [0 1]
]]
sage: Set(L[0][1:])==Set(L[1][1:])
False
Quite unexpected... However :
sage: all([u in Set(L[1][1:]) for u in Set(L[0][1:])])
True
sage: all([u in Set(L[0][1:]) for u in Set(L[1][1:])])
True
as expected.
The Sets reference doesn't mention testing forv Sets equality.
Is that a bug, an oversight or an expected behaviour ?
 
 