Problem: f(x,g(x),y) -> p(h(x),y) f(x,y,z) -> f(x,g(x),z) g(x) -> h(x) Proof: Church Rosser Transformation Processor (no redundant rules): strict: weak: critical peaks: 3 f(x,h(x),y) <-0|1[]- f(x,g(x),y) -2|[]-> p(h(x),y) f(x,g(x),y) <-1|[]- f(x,g(x),y) -2|[]-> p(h(x),y) p(h(x),z) <-2|[]- f(x,g(x),z) -1|[]-> f(x,g(x),z) Redundant Rules Transformation: g(x) -> h(x) f(x,y,z) -> f(x,g(x),z) f(x,g(x),y) -> p(h(x),y) f(x,y,z) -> f(x,h(x),z) f(x,y,z) -> p(h(x),z) Church Rosser Transformation Processor (no redundant rules): strict: weak: critical peaks: 6 p(h(x),z) <-0|[]- f(x,y,z) -1|[]-> f(x,h(x),z) p(h(x),z) <-0|[]- f(x,y,z) -2|[]-> f(x,g(x),z) f(x,h(x),z) <-1|[]- f(x,y,z) -0|[]-> p(h(x),z) f(x,h(x),z) <-1|[]- f(x,y,z) -2|[]-> f(x,g(x),z) f(x,g(x),z) <-2|[]- f(x,y,z) -0|[]-> p(h(x),z) f(x,g(x),z) <-2|[]- f(x,y,z) -1|[]-> f(x,h(x),z) Redundant Rules Transformation: f(x,y,z) -> p(h(x),z) f(x,y,z) -> f(x,h(x),z) f(x,y,z) -> f(x,g(x),z) g(x) -> h(x) Church Rosser Transformation Processor (no redundant rules): strict: g(x) -> h(x) f(x,y,z) -> f(x,g(x),z) f(x,y,z) -> f(x,h(x),z) f(x,y,z) -> p(h(x),z) weak: critical peaks: 6 f(x,g(x),z) <-1|[]- f(x,y,z) -2|[]-> f(x,h(x),z) f(x,g(x),z) <-1|[]- f(x,y,z) -3|[]-> p(h(x),z) f(x,h(x),z) <-2|[]- f(x,y,z) -1|[]-> f(x,g(x),z) f(x,h(x),z) <-2|[]- f(x,y,z) -3|[]-> p(h(x),z) p(h(x),z) <-3|[]- f(x,y,z) -1|[]-> f(x,g(x),z) p(h(x),z) <-3|[]- f(x,y,z) -2|[]-> f(x,h(x),z) Closedness Processor (*development*): Qed