On Tue, Aug 2, 2011 at 12:21 PM, Johannes <dajo.m...@web.de> wrote: > Hi list > i need to construct two morphisms > f:ZZ^n \to Z given by a diagonalmatrix > and g: ZZ -> Z/dZ > > because I have to find the kernel of the compositoin. > consturcting g was no problem by g = ZZ.hom(ZZ.quotient(ZZ.ideal(d))) > father, getting the kernel of f as matrix worked too. > but how to get the kernel of the compositoin? >
I'll speak in code: sage: f = Hom(ZZ^3, ZZ^1)([1,2,3]) sage: g = Hom(ZZ^1, ZZ.quotient_ring(7)^1)([1]) sage: g * f Free module morphism defined by the matrix [1] [2] [3] Domain: Ambient free module of rank 3 over the principal ideal domain ... Codomain: Vector space of dimension 1 over Ring of integers modulo 7 sage: h = g * f sage: h.kernel() Free module of degree 3 and rank 2 over Integer Ring Echelon basis matrix: [ 1 1 -1] [ 0 3 -2] -- william -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
