Simplication lose variables.

[Isomorph70]

In> sf(a,x):=Sum(k,1,LLength(a),f(a[k].x)); Out> True In> sf(a,{z,y}) Out> Sum(k,1,LLength(a),f(a[k].x))

The list/vector {z,y} is missing in the final output. (Version 1.7.0)