Does anyone have any tips for how to compute the kernel of a map between polynomial algebras, or for checking whether the map is injective? I have families of such maps involving algebras with many generators. I'm working over GF(2), if that matters. In one example I defined the map phi: R -> S where R has 12 generators, S has 19 generators, and did
sage: phi.is_injective() After about 30 hours, Sage quit on me, perhaps running out of memory ("Killed: 9"). An example of the sort of map I'm interested in: sage: phi Ring morphism: From: Multivariate Polynomial Ring in h20, h21, h30, h31, h40, h41, h50 over Finite Field of size 2 To: Multivariate Polynomial Ring in h20, h21, h30, h31, h40, h41, h50, xi1, xi2, xi3, xi4, xi5 over Finite Field of size 2 Defn: h20 |--> h20 h21 |--> h21 h30 |--> h20*xi1^4 + h21*xi1 + h30 h31 |--> h21*xi1^8 + h31 h40 |--> h21*xi1^9 + h30*xi1^8 + h20*xi2^4 + h31*xi1 h41 |--> h31*xi1^16 + h21*xi2^8 h50 |--> h31*xi1^17 + h21*xi1*xi2^8 + h30*xi2^8 + h20*xi3^4 Any suggestions? -- John -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/97318b8e-f4c9-4af3-a8ff-b901a4f2c971n%40googlegroups.com.