The system is accessible function passing by a sort ordering that equates all sorts.

We start by computing the following initial DP problem:

  P1. (1) lessthan#(arrow(X, Y), arrow(U, V)) => lessthan#(U, X)
      (2) lessthan#(arrow(X, Y), arrow(U, V)) => lessthan#(Y, V)

***** No progress could be made on DP problem P1.