Ask Your Question

How are free group homomorphisms implemented?

asked 2013-10-22 18:11:52 -0600

glaun gravatar image

updated 2013-10-22 18:12:27 -0600

I see from the documentation that homomorphisms are implemented for matrix groups, symmetric groups, and abelian groups. I would assume that homomorphisms would be implemented for free groups, but I get an error if I do the following:

sage: F.<a,b> = FreeGroup(2)

sage: F.hom([a,b]) # Should be unique homomorphism with a |--> a, b |--> b

TypeError Traceback (most recent call last) ...

TypeError: Unable to coerce x (=[a, b]) to a morphism in Set of Morphisms from Free Group on generators {a, b} to Free Group on generators {a, b} in Category of groups

Do I have the syntax wrong, or are these not implemented?

edit retag flag offensive close merge delete

1 answer

Sort by ยป oldest newest most voted

answered 2013-10-22 23:51:28 -0600

vdelecroix gravatar image


Free group are currently implemented using GAP and it seems that morphisms are not supported.

You may have a look at sage-train-track where a ad-hoc implementation of FreeGroup is provided together with its automorphisms... and much more.

edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools


Asked: 2013-10-22 18:11:52 -0600

Seen: 222 times

Last updated: Oct 22 '13