This was just a brief moment of thought over a year ago, but I can try to summarize. I was thinking about how to unify variables in certain simple Datalog settings. If we think of a clause as a vector of variables, then simple unifications can look like just a gather operation. A gather can be thought of as a matrix-vector multiplication, but that's not really useful (performance wise). But if those variables are also in a linear equation, then it becomes possibly-useful, e.g. for something like `P(x, y) :- E(x, 3x+4y)`