<div id="comment:0"></div> The code ``` G = SL(2,ZZ) M = matrix([[1,0],[0,1]]) M in G ``` runs possibly forever inside GAP. same for ``` M = matrix(ZZ,[[1,0],[0,1]]) ``` Component: **group theory** _Issue created by migration from https://trac.sagemath.org/ticket/1646_