Thomas Kahle
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Hello,
Does M2 compute minimal free resolutions over quotient rings? Here is a
an example where a non-minimal resolution is produced. Is there some
command to trim it (I tried 'trim' (not defined) and 'prune' (does
nothing))?
R = QQ[a,b,c,d]/(a*b-c*d)
J = ideal (a*b*c, c^2*d)
-- The rewriting works
2 2
o24 = ideal (c d, c d)
i26 : mingens J
o26 = | c2d |
-- mingens also works but
i27 : betti res J
0 1 2
o27 = total: 1 2 1
0: 1 . .
1: . . 1
2: . 2 .
-- The resolution is not minimized:
i35 : (res J).dd#2
o35 = {3} | -1 |
{3} | 1 |
Cheers,
Thomas
--
Thomas Kahle