YES Problem: a() -> c() c() -> a() d() -> a() b() -> d() a() -> b() a() -> e() d() -> e() Proof: Church Rosser Transformation Processor (critical pair closing system, Thm 2.11): c() -> a() a() -> b() a() -> e() b() -> d() d() -> e() critical peaks: joinable Matrix Interpretation Processor: dim=1 interpretation: [e] = 0, [c] = 4, [b] = 4, [a] = 4, [d] = 0 orientation: c() = 4 >= 4 = a() a() = 4 >= 4 = b() a() = 4 >= 0 = e() b() = 4 >= 0 = d() d() = 0 >= 0 = e() problem: c() -> a() a() -> b() d() -> e() Matrix Interpretation Processor: dim=1 interpretation: [e] = 0, [c] = 0, [b] = 0, [a] = 0, [d] = 1 orientation: c() = 0 >= 0 = a() a() = 0 >= 0 = b() d() = 1 >= 0 = e() problem: c() -> a() a() -> b() Matrix Interpretation Processor: dim=1 interpretation: [c] = 4, [b] = 0, [a] = 4 orientation: c() = 4 >= 4 = a() a() = 4 >= 0 = b() problem: c() -> a() Matrix Interpretation Processor: dim=1 interpretation: [c] = 1, [a] = 0 orientation: c() = 1 >= 0 = a() problem: Qed