id summary reporter owner description type status priority milestone component resolution keywords cc merged author reviewer upstream work_issues branch commit dependencies stopgaps
25520 Wrong 0th symbolic power of a matrix tmonteil "From [https://ask.sagemath.org/question/42532/more-problems-with-general-power-of-a-matrix/ this ask question], the symbolic power of a matrix gives a result that is correct when restricted to positive integers, but wrong on 0:
{{{
sage: A = matrix(QQbar,3,3,[[-2,-8,-12],[1,4,4],[0,0,1]])
sage: k = SR.var('k')
sage: B = A^k
sage: B
[ -2^k -4*2^k -4*2^k - 4]
[ 1/2*2^k 2*2^k 2*2^k]
[ 0 0 1]
sage: [B.subs(k=i) == A^i for i in range(20)]
[False,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True,
True]
sage: B.subs(k=0)
[ -1 -4 -8]
[1/2 2 2]
[ 0 0 1]
}}}
" defect new major sage-8.3 symbolics mforets slelievre N/A