On Sat, Mar 17, 2012 at 10:11 PM, David Joyner <wdjoy...@gmail.com> wrote: > On Sat, Mar 17, 2012 at 3:55 PM, krastanov.ste...@gmail.com > <krastanov.ste...@gmail.com> wrote: >>> >>> Is this necessary? All groups are isomorphic to the permutation group >>> anyway. Groups for specific structures can make use of functionality >>> implemented for them (matrix group -> sympy matrices, galois -> polys) >>> for basic operations and can implement the mapping to the perm group >>> module for group theoretic operations. >>> >> >> This seems incorrect. Zn is abelian for example and it is not >> isomorphic to any permutation group. Moreover, there are all the >> continuous groups. > > > It is not correct to say Zn (I assume you mean the ring of integers > mod n) is not isomorphic to a permutation group. (Consider the > cyclic group generated by the n-cycle (1,2,...,n) in disjoint > cycle notation.)
I think difference should be made between nZ = {n * k | k\in Z} and Z_n = {k mod n | k\in Z}. Z_n is finite, while nZ is infinite. This might be the reason for the misunderstanding. Sergiu -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.