Linearity Assumption [duplicate]

I'd like to define a set of variables of this sort:

{K1[t],K2[t],...}


Adding a general assumption: all such variables are linear. I'd like to do this to avoid Mathematica having to show me higher order derivatives of these functions in my solution.

• I think the questions are different. In this case I've been asking "assumptions". In question you mentioned above, I was asking a "truncation". – Mirko Aveta Feb 23 '19 at 19:46

K1 /: Derivative[k_][K1] /; k >= 2 := (0 &)