YES We show the termination of the TRS R: app(app(and(),true()),true()) -> true() app(app(and(),true()),false()) -> false() app(app(and(),false()),true()) -> false() app(app(and(),false()),false()) -> false() app(app(or(),true()),true()) -> true() app(app(or(),true()),false()) -> true() app(app(or(),false()),true()) -> true() app(app(or(),false()),false()) -> false() app(app(forall(),p),nil()) -> true() app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) app(app(forsome(),p),nil()) -> false() app(app(forsome(),p),app(app(cons(),x),xs)) -> app(app(or(),app(p,x)),app(app(forsome(),p),xs)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(forall(),p),app(app(cons(),x),xs)) -> app#(app(and(),app(p,x)),app(app(forall(),p),xs)) p2: app#(app(forall(),p),app(app(cons(),x),xs)) -> app#(and(),app(p,x)) p3: app#(app(forall(),p),app(app(cons(),x),xs)) -> app#(p,x) p4: app#(app(forall(),p),app(app(cons(),x),xs)) -> app#(app(forall(),p),xs) p5: app#(app(forsome(),p),app(app(cons(),x),xs)) -> app#(app(or(),app(p,x)),app(app(forsome(),p),xs)) p6: app#(app(forsome(),p),app(app(cons(),x),xs)) -> app#(or(),app(p,x)) p7: app#(app(forsome(),p),app(app(cons(),x),xs)) -> app#(p,x) p8: app#(app(forsome(),p),app(app(cons(),x),xs)) -> app#(app(forsome(),p),xs) and R consists of: r1: app(app(and(),true()),true()) -> true() r2: app(app(and(),true()),false()) -> false() r3: app(app(and(),false()),true()) -> false() r4: app(app(and(),false()),false()) -> false() r5: app(app(or(),true()),true()) -> true() r6: app(app(or(),true()),false()) -> true() r7: app(app(or(),false()),true()) -> true() r8: app(app(or(),false()),false()) -> false() r9: app(app(forall(),p),nil()) -> true() r10: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r11: app(app(forsome(),p),nil()) -> false() r12: app(app(forsome(),p),app(app(cons(),x),xs)) -> app(app(or(),app(p,x)),app(app(forsome(),p),xs)) The estimated dependency graph contains the following SCCs: {p3, p4, p7, p8} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(forall(),p),app(app(cons(),x),xs)) -> app#(p,x) p2: app#(app(forsome(),p),app(app(cons(),x),xs)) -> app#(app(forsome(),p),xs) p3: app#(app(forsome(),p),app(app(cons(),x),xs)) -> app#(p,x) p4: app#(app(forall(),p),app(app(cons(),x),xs)) -> app#(app(forall(),p),xs) and R consists of: r1: app(app(and(),true()),true()) -> true() r2: app(app(and(),true()),false()) -> false() r3: app(app(and(),false()),true()) -> false() r4: app(app(and(),false()),false()) -> false() r5: app(app(or(),true()),true()) -> true() r6: app(app(or(),true()),false()) -> true() r7: app(app(or(),false()),true()) -> true() r8: app(app(or(),false()),false()) -> false() r9: app(app(forall(),p),nil()) -> true() r10: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r11: app(app(forsome(),p),nil()) -> false() r12: app(app(forsome(),p),app(app(cons(),x),xs)) -> app(app(or(),app(p,x)),app(app(forsome(),p),xs)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. lexicographic path order with precedence: precedence: forsome > app# > forall > app > cons argument filter: pi(app#) = 1 pi(app) = 2 pi(forall) = [] pi(cons) = [] pi(forsome) = [] 2. matrix interpretations: carrier: N^3 order: lexicographic order interpretations: app#_A(x1,x2) = ((1,0,0),(0,1,0),(1,1,1)) x1 app_A(x1,x2) = ((1,0,0),(1,1,0),(1,1,1)) x2 + (1,1,1) forall_A() = (1,1,1) cons_A() = (1,1,0) forsome_A() = (1,1,1) The next rules are strictly ordered: p1, p3 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(forsome(),p),app(app(cons(),x),xs)) -> app#(app(forsome(),p),xs) p2: app#(app(forall(),p),app(app(cons(),x),xs)) -> app#(app(forall(),p),xs) and R consists of: r1: app(app(and(),true()),true()) -> true() r2: app(app(and(),true()),false()) -> false() r3: app(app(and(),false()),true()) -> false() r4: app(app(and(),false()),false()) -> false() r5: app(app(or(),true()),true()) -> true() r6: app(app(or(),true()),false()) -> true() r7: app(app(or(),false()),true()) -> true() r8: app(app(or(),false()),false()) -> false() r9: app(app(forall(),p),nil()) -> true() r10: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r11: app(app(forsome(),p),nil()) -> false() r12: app(app(forsome(),p),app(app(cons(),x),xs)) -> app(app(or(),app(p,x)),app(app(forsome(),p),xs)) The estimated dependency graph contains the following SCCs: {p1} {p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(forsome(),p),app(app(cons(),x),xs)) -> app#(app(forsome(),p),xs) and R consists of: r1: app(app(and(),true()),true()) -> true() r2: app(app(and(),true()),false()) -> false() r3: app(app(and(),false()),true()) -> false() r4: app(app(and(),false()),false()) -> false() r5: app(app(or(),true()),true()) -> true() r6: app(app(or(),true()),false()) -> true() r7: app(app(or(),false()),true()) -> true() r8: app(app(or(),false()),false()) -> false() r9: app(app(forall(),p),nil()) -> true() r10: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r11: app(app(forsome(),p),nil()) -> false() r12: app(app(forsome(),p),app(app(cons(),x),xs)) -> app(app(or(),app(p,x)),app(app(forsome(),p),xs)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. lexicographic path order with precedence: precedence: app# > cons > app > forsome argument filter: pi(app#) = [1, 2] pi(app) = [1, 2] pi(forsome) = [] pi(cons) = [] 2. matrix interpretations: carrier: N^3 order: lexicographic order interpretations: app#_A(x1,x2) = ((1,0,0),(1,0,0),(1,1,0)) x2 app_A(x1,x2) = ((1,0,0),(0,1,0),(1,1,0)) x1 + ((1,0,0),(1,1,0),(0,0,0)) x2 forsome_A() = (0,0,0) cons_A() = (1,1,0) The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(forall(),p),app(app(cons(),x),xs)) -> app#(app(forall(),p),xs) and R consists of: r1: app(app(and(),true()),true()) -> true() r2: app(app(and(),true()),false()) -> false() r3: app(app(and(),false()),true()) -> false() r4: app(app(and(),false()),false()) -> false() r5: app(app(or(),true()),true()) -> true() r6: app(app(or(),true()),false()) -> true() r7: app(app(or(),false()),true()) -> true() r8: app(app(or(),false()),false()) -> false() r9: app(app(forall(),p),nil()) -> true() r10: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r11: app(app(forsome(),p),nil()) -> false() r12: app(app(forsome(),p),app(app(cons(),x),xs)) -> app(app(or(),app(p,x)),app(app(forsome(),p),xs)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. lexicographic path order with precedence: precedence: app# > cons > app > forall argument filter: pi(app#) = [1, 2] pi(app) = [1, 2] pi(forall) = [] pi(cons) = [] 2. matrix interpretations: carrier: N^3 order: lexicographic order interpretations: app#_A(x1,x2) = ((1,0,0),(1,0,0),(1,1,0)) x2 app_A(x1,x2) = ((1,0,0),(0,1,0),(1,1,0)) x1 + ((1,0,0),(1,1,0),(0,0,0)) x2 forall_A() = (0,0,0) cons_A() = (1,1,0) The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.