Here is a related question, but not quite what I’m after. I would like to define a function f[x_] that has the distributive attribute, such that: f[a+b+c] f[a]+f[b]+f[c] Of course I could do f[Plus[x_,y___]]:=f[x]+f[Plus[y]] but I suspect that this would be much slower than an actual Attribute. Unfortunately, I cannot find Distributive in the listRead more