sage: M = matrix([[1,1,1,1,1,1],[1,1,-2,1,1,-2],[-2,1,1,-2,1,1],
[1,-2,1,1,-2,1]])
sage: M
[ 1  1  1  1  1  1]
[ 1  1 -2  1  1 -2]
[-2  1  1 -2  1  1]
[ 1 -2  1  1 -2  1]
sage: M.row_space()
Free module of degree 6 and rank 3 over Integer Ring
Echelon basis matrix:
[1 1 1 1 1 1]
[0 3 0 0 3 0]
[0 0 3 0 0 3]
sage: M.row_space().zero()
(0, 0, 0, 0, 0, 0)
sage: vector([1,0,0,1,0,0]) in M.row_space()
False
sage: vector(ZZ,[1,0,0,1,0,0])
(1, 0, 0, 1, 0, 0)
sage: vector(ZZ,[1,0,0,1,0,0]) in M.row_space()
False

I guess I'm a little surprised that even the 'vector' explicitly
designated to be over ZZ isn't in there.  I think I'm mathematically
ok, too - taking the echelon matrix, isn't my vector e_1-(1/3)*e_2-
(1/3)*e_3 ?  Anyway, I hope that I'm just misusing free modules and
vectors - though since my vector isn't really one, it would seem
reasonable to let it live in the free module.

Thanks for any assistance,
- kcrisman

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