YES (VAR x0 x2 x1 x y) (RULES d(x0,d(x2,x1)) -> d(d(x0,i(x1)),x2) d(d(x0,i(x1)),x1) -> x0 d(x0,one()) -> x0 i(one()) -> one() i(d(x0,x1)) -> d(x1,x0) d(d(x0,x1),i(x1)) -> x0 *(x,y) -> d(x,i(y)) i(i(y)) -> y d(one(),y) -> i(y) d(x,x) -> one() ) (COMMENT Termination is shown by EKBO with interpretations on natural numbers d_A(x1,x2) = x1 + x2 + 1 one_A = 1 i_A(x1) = x1 *_A(x1,x2) = x1 + x2 + 1 d#_A(x1,x2) = x2 one#_A = 0 *#_A(x1,x2) = x1 + x2 weights w0 = 1 w(d) = 0 w(one) = 1 w(i) = 0 w(*) = 0 and precedence: i > * > d > one )