YES We show the termination of the TRS R: *(x,*(minus(y),y)) -> *(minus(*(y,y)),x) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: *#(x,*(minus(y),y)) -> *#(minus(*(y,y)),x) p2: *#(x,*(minus(y),y)) -> *#(y,y) and R consists of: r1: *(x,*(minus(y),y)) -> *(minus(*(y,y)),x) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: *#(x,*(minus(y),y)) -> *#(minus(*(y,y)),x) p2: *#(x,*(minus(y),y)) -> *#(y,y) and R consists of: r1: *(x,*(minus(y),y)) -> *(minus(*(y,y)),x) The set of usable rules consists of r1 Take the reduction pair: lexicographic combination of reduction pairs: 1. matrix interpretations: carrier: N^4 order: lexicographic order interpretations: *#_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(1,0,1,0),(1,0,0,1)) x1 + x2 *_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(1,1,1,0),(0,0,0,1)) x1 + ((1,0,0,0),(0,0,0,0),(1,1,0,0),(0,0,0,0)) x2 + (1,2,2,1) minus_A(x1) = x1 + (1,0,1,1) 2. lexicographic path order with precedence: precedence: minus > *# > * argument filter: pi(*#) = [1, 2] pi(*) = [] pi(minus) = [] The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains.