We consider universal computability of the MSTRS with no additional rule schemes:

  Signature: a :: o
             b :: o
             f :: o -> o -> o
             h :: o -> o

  Rules: f(x, x) -> x
         f(a, y) -> f(y, b)

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

We start by computing the initial DP problem D1 = (P1, R UNION R_?, i, c), where:

  P1. (1) f#(a, y) => f#(y, b)

***** No progress could be made on DP problem D1 = (P1, R UNION R_?, i, c).