2020-04-11 21:05:49 +0200 commented question Definition of symbolic functions on path algebra thank you. 2020-04-11 14:55:20 +0200 commented question Definition of symbolic functions on path algebra Do you have any idea from where I can start? I want a linear map "d" that gives d(xy) = d(x)y+xd(y).where x,y in PathAlgebra. 2020-04-11 12:30:43 +0200 commented question Definition of symbolic functions on path algebra Thanks, I want to create derivations on path algebras. 2020-04-11 10:13:36 +0200 received badge ● Student (source) 2020-04-10 19:56:59 +0200 received badge ● Editor (source) 2020-04-10 18:54:37 +0200 asked a question Definition of symbolic functions on path algebra I tried to define a symbolic function on path algbera like that: G = DiGraph({1:{2:['a']}, 2:{3:['b']}}) P = G.path_semigroup() A = P.algebra(GF(7)) A.inject_variables() def ev(self, x): return 2*x foo = function("foo", nargs=1, eval_func=ev) foo(a)  But I get an error: TypeError: cannot coerce arguments: no canonical coercion from Path algebra of Multi-digraph on 3 vertices over Finite Field of size 7 to Symbolic Ring. My question how can I define a symbolic function to accept path algebra variables? Thanks.