>> I don't think you can have automated conversion like C(a^2 + b^2) since it >> makes sense to define: >> sage: C = CombinatorialFreeModule(QQ, [ a^2, b^2, a*b, a^2+b^2 ]) >> sage: 2*C.basis()[a^2] + C.basis()[b^2] >> B[b^2] + 2*B[a^2] >> sage: 2*C.basis()[a^2] + C.basis()[b^2 + a^2] >> 2*B[a^2] + B[a^2 + b^2] >> >> Then C(a^2 + b^2) would be ambiguous. > > I gathered some of this from the examples and documentation, but > unfortunately it makes this not so useful for my purpose, which is > realizing a finite-dimensional quotient QQ[x1, ... ,xn]/I as a vector space > over QQ. One can do this by hand, but it gets old fast :( Can one index > by infinite sets with this code?
Sure ! sage: C = CombinatorialFreeModule(QQ, Permutations()) sage: C.basis()[Permutation(range(1, 100))] B[[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99]] Note that here since Permutations() is more than a list (it a close to be a parent with elements, and will become), a much simpler conversion syntax can be used: sage: C([1,2,3]) + C([1,2]) + C(range(1, 100)) B[[1, 2]] + B[[1, 2, 3]] + B[[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99]] So maybe this is was you want: sage: MPR = a.parent(); MPR Multivariate Polynomial Ring in a, b over Rational Field sage: C = CombinatorialFreeModule(QQ, MPR) sage: C(a^2) B[a^2] sage: C(a^2)+C(b^2) B[b^2] + B[a^2] Cheers, Florent -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
