MAYBE Problem: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) Proof: DP Processor: DPs: active#(f(a(),b(),X)) -> f#(X,X,X) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) active#(c()) -> mark#(a()) active#(c()) -> mark#(b()) mark#(f(X1,X2,X3)) -> mark#(X3) mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) mark#(a()) -> active#(a()) mark#(b()) -> active#(b()) mark#(c()) -> active#(c()) f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,active(X3)) -> f#(X1,X2,X3) TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) TDG Processor: DPs: active#(f(a(),b(),X)) -> f#(X,X,X) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) active#(c()) -> mark#(a()) active#(c()) -> mark#(b()) mark#(f(X1,X2,X3)) -> mark#(X3) mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) mark#(a()) -> active#(a()) mark#(b()) -> active#(b()) mark#(c()) -> active#(c()) f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,active(X3)) -> f#(X1,X2,X3) TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) graph: mark#(c()) -> active#(c()) -> active#(c()) -> mark#(b()) mark#(c()) -> active#(c()) -> active#(c()) -> mark#(a()) mark#(c()) -> active#(c()) -> active#(f(a(),b(),X)) -> mark#(f(X,X,X)) mark#(c()) -> active#(c()) -> active#(f(a(),b(),X)) -> f#(X,X,X) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(c()) -> active#(c()) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(b()) -> active#(b()) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(a()) -> active#(a()) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(f(X1,X2,X3)) -> mark#(X3) mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,active(X3)) -> f#(X1,X2,X3) mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) -> f#(X1,active(X2),X3) -> f#(X1,X2,X3) mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) -> f#(active(X1),X2,X3) -> f#(X1,X2,X3) mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) -> f#(X1,mark(X2),X3) -> f#(X1,X2,X3) mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) -> f#(mark(X1),X2,X3) -> f#(X1,X2,X3) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) -> active#(c()) -> mark#(b()) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) -> active#(c()) -> mark#(a()) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) -> active#(f(a(),b(),X)) -> mark#(f(X,X,X)) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) -> active#(f(a(),b(),X)) -> f#(X,X,X) mark#(b()) -> active#(b()) -> active#(c()) -> mark#(b()) mark#(b()) -> active#(b()) -> active#(c()) -> mark#(a()) mark#(b()) -> active#(b()) -> active#(f(a(),b(),X)) -> mark#(f(X,X,X)) mark#(b()) -> active#(b()) -> active#(f(a(),b(),X)) -> f#(X,X,X) mark#(a()) -> active#(a()) -> active#(c()) -> mark#(b()) mark#(a()) -> active#(a()) -> active#(c()) -> mark#(a()) mark#(a()) -> active#(a()) -> active#(f(a(),b(),X)) -> mark#(f(X,X,X)) mark#(a()) -> active#(a()) -> active#(f(a(),b(),X)) -> f#(X,X,X) f#(mark(X1),X2,X3) -> f#(X1,X2,X3) -> f#(X1,X2,active(X3)) -> f#(X1,X2,X3) f#(mark(X1),X2,X3) -> f#(X1,X2,X3) -> f#(X1,active(X2),X3) -> f#(X1,X2,X3) f#(mark(X1),X2,X3) -> f#(X1,X2,X3) -> f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(mark(X1),X2,X3) -> f#(X1,X2,X3) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) f#(mark(X1),X2,X3) -> f#(X1,X2,X3) -> f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(mark(X1),X2,X3) -> f#(X1,X2,X3) -> f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) -> f#(X1,X2,active(X3)) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) -> f#(X1,active(X2),X3) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) -> f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) -> f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) -> f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) -> f#(X1,X2,active(X3)) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) -> f#(X1,active(X2),X3) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) -> f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) -> f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) -> f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) -> f#(X1,X2,active(X3)) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) -> f#(X1,active(X2),X3) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) -> f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) -> f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) -> f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) -> f#(X1,X2,active(X3)) -> f#(X1,X2,X3) f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) -> f#(X1,active(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) -> f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) -> f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) -> f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,X2,active(X3)) -> f#(X1,X2,X3) -> f#(X1,X2,active(X3)) -> f#(X1,X2,X3) f#(X1,X2,active(X3)) -> f#(X1,X2,X3) -> f#(X1,active(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,active(X3)) -> f#(X1,X2,X3) -> f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,X2,active(X3)) -> f#(X1,X2,X3) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) f#(X1,X2,active(X3)) -> f#(X1,X2,X3) -> f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,active(X3)) -> f#(X1,X2,X3) -> f#(mark(X1),X2,X3) -> f#(X1,X2,X3) active#(c()) -> mark#(b()) -> mark#(c()) -> active#(c()) active#(c()) -> mark#(b()) -> mark#(b()) -> active#(b()) active#(c()) -> mark#(b()) -> mark#(a()) -> active#(a()) active#(c()) -> mark#(b()) -> mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) active#(c()) -> mark#(b()) -> mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) active#(c()) -> mark#(b()) -> mark#(f(X1,X2,X3)) -> mark#(X3) active#(c()) -> mark#(a()) -> mark#(c()) -> active#(c()) active#(c()) -> mark#(a()) -> mark#(b()) -> active#(b()) active#(c()) -> mark#(a()) -> mark#(a()) -> active#(a()) active#(c()) -> mark#(a()) -> mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) active#(c()) -> mark#(a()) -> mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) active#(c()) -> mark#(a()) -> mark#(f(X1,X2,X3)) -> mark#(X3) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) -> mark#(c()) -> active#(c()) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) -> mark#(b()) -> active#(b()) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) -> mark#(a()) -> active#(a()) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) -> mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) -> mark#(f(X1,X2,X3)) -> f#(X1,X2,mark(X3)) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) -> mark#(f(X1,X2,X3)) -> mark#(X3) active#(f(a(),b(),X)) -> f#(X,X,X) -> f#(X1,X2,active(X3)) -> f#(X1,X2,X3) active#(f(a(),b(),X)) -> f#(X,X,X) -> f#(X1,active(X2),X3) -> f#(X1,X2,X3) active#(f(a(),b(),X)) -> f#(X,X,X) -> f#(active(X1),X2,X3) -> f#(X1,X2,X3) active#(f(a(),b(),X)) -> f#(X,X,X) -> f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) active#(f(a(),b(),X)) -> f#(X,X,X) -> f#(X1,mark(X2),X3) -> f#(X1,X2,X3) active#(f(a(),b(),X)) -> f#(X,X,X) -> f#(mark(X1),X2,X3) -> f#(X1,X2,X3) SCC Processor: #sccs: 2 #rules: 14 #arcs: 88/256 DPs: mark#(c()) -> active#(c()) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) mark#(f(X1,X2,X3)) -> mark#(X3) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) active#(c()) -> mark#(a()) mark#(a()) -> active#(a()) active#(c()) -> mark#(b()) mark#(b()) -> active#(b()) TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) EDG Processor: DPs: mark#(c()) -> active#(c()) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) mark#(f(X1,X2,X3)) -> mark#(X3) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) active#(c()) -> mark#(a()) mark#(a()) -> active#(a()) active#(c()) -> mark#(b()) mark#(b()) -> active#(b()) TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) graph: mark#(c()) -> active#(c()) -> active#(c()) -> mark#(a()) mark#(c()) -> active#(c()) -> active#(c()) -> mark#(b()) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(f(X1,X2,X3)) -> mark#(X3) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(a()) -> active#(a()) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(b()) -> active#(b()) mark#(f(X1,X2,X3)) -> mark#(X3) -> mark#(c()) -> active#(c()) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) -> active#(f(a(),b(),X)) -> mark#(f(X,X,X)) active#(c()) -> mark#(b()) -> mark#(b()) -> active#(b()) active#(c()) -> mark#(a()) -> mark#(a()) -> active#(a()) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) -> mark#(f(X1,X2,X3)) -> mark#(X3) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) -> mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) SCC Processor: #sccs: 1 #rules: 3 #arcs: 12/64 DPs: mark#(f(X1,X2,X3)) -> mark#(X3) mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) KBO Processor: argument filtering: pi(a) = [] pi(b) = [] pi(f) = [2] pi(active) = 0 pi(mark) = 0 pi(c) = [] pi(active#) = 0 pi(mark#) = 0 weight function: w0 = 1 w(c) = w(active) = w(f) = w(b) = w(a) = 1 w(mark#) = w(active#) = w(mark) = 0 precedence: c > mark# ~ active# ~ mark ~ active ~ f ~ b ~ a problem: DPs: mark#(f(X1,X2,X3)) -> active#(f(X1,X2,mark(X3))) active#(f(a(),b(),X)) -> mark#(f(X,X,X)) TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) Open DPs: f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,mark(X3)) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) f#(X1,X2,active(X3)) -> f#(X1,X2,X3) TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) Subterm Criterion Processor: simple projection: pi(f#) = 2 problem: DPs: f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,mark(X2),X3) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) f#(X1,active(X2),X3) -> f#(X1,X2,X3) TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) Subterm Criterion Processor: simple projection: pi(f#) = 1 problem: DPs: f#(mark(X1),X2,X3) -> f#(X1,X2,X3) f#(active(X1),X2,X3) -> f#(X1,X2,X3) TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) Subterm Criterion Processor: simple projection: pi(f#) = 0 problem: DPs: TRS: active(f(a(),b(),X)) -> mark(f(X,X,X)) active(c()) -> mark(a()) active(c()) -> mark(b()) mark(f(X1,X2,X3)) -> active(f(X1,X2,mark(X3))) mark(a()) -> active(a()) mark(b()) -> active(b()) mark(c()) -> active(c()) f(mark(X1),X2,X3) -> f(X1,X2,X3) f(X1,mark(X2),X3) -> f(X1,X2,X3) f(X1,X2,mark(X3)) -> f(X1,X2,X3) f(active(X1),X2,X3) -> f(X1,X2,X3) f(X1,active(X2),X3) -> f(X1,X2,X3) f(X1,X2,active(X3)) -> f(X1,X2,X3) Qed