YES We show the termination of the TRS R: app(app(and(),true()),true()) -> true() app(app(and(),x),false()) -> false() app(app(and(),false()),y) -> false() app(app(or(),true()),y) -> true() app(app(or(),x),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(),x),false()) -> false() r3: app(app(and(),false()),y) -> false() r4: app(app(or(),true()),y) -> true() r5: app(app(or(),x),true()) -> true() r6: app(app(or(),false()),false()) -> false() r7: app(app(forall(),p),nil()) -> true() r8: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r9: app(app(forsome(),p),nil()) -> false() r10: 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(),x),false()) -> false() r3: app(app(and(),false()),y) -> false() r4: app(app(or(),true()),y) -> true() r5: app(app(or(),x),true()) -> true() r6: app(app(or(),false()),false()) -> false() r7: app(app(forall(),p),nil()) -> true() r8: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r9: app(app(forsome(),p),nil()) -> false() r10: 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. weighted path order base order: max/plus interpretations on natural numbers: app#_A(x1,x2) = max{x1 + 1, x2 - 5} app_A(x1,x2) = max{14, x1 + 3, x2 + 11} forall_A = 13 cons_A = 9 forsome_A = 1 precedence: app# = app = forall = cons = forsome partial status: pi(app#) = [1] pi(app) = [1, 2] pi(forall) = [] pi(cons) = [] pi(forsome) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: app#_A(x1,x2) = x1 + 4 app_A(x1,x2) = max{x1 + 8, x2 + 10} forall_A = 7 cons_A = 8 forsome_A = 9 precedence: app# = app = forall = cons = forsome partial status: pi(app#) = [1] pi(app) = [] pi(forall) = [] pi(cons) = [] pi(forsome) = [] 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(),x),false()) -> false() r3: app(app(and(),false()),y) -> false() r4: app(app(or(),true()),y) -> true() r5: app(app(or(),x),true()) -> true() r6: app(app(or(),false()),false()) -> false() r7: app(app(forall(),p),nil()) -> true() r8: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r9: app(app(forsome(),p),nil()) -> false() r10: 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(),x),false()) -> false() r3: app(app(and(),false()),y) -> false() r4: app(app(or(),true()),y) -> true() r5: app(app(or(),x),true()) -> true() r6: app(app(or(),false()),false()) -> false() r7: app(app(forall(),p),nil()) -> true() r8: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r9: app(app(forsome(),p),nil()) -> false() r10: 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. weighted path order base order: max/plus interpretations on natural numbers: app#_A(x1,x2) = max{0, x2 - 4} app_A(x1,x2) = max{x1 + 6, x2 + 3} forsome_A = 2 cons_A = 3 precedence: app# = app = forsome = cons partial status: pi(app#) = [] pi(app) = [1, 2] pi(forsome) = [] pi(cons) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: app#_A(x1,x2) = 0 app_A(x1,x2) = max{x1 + 2, x2 + 6} forsome_A = 3 cons_A = 4 precedence: app# = app = forsome = cons partial status: pi(app#) = [] pi(app) = [1, 2] pi(forsome) = [] pi(cons) = [] 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(),x),false()) -> false() r3: app(app(and(),false()),y) -> false() r4: app(app(or(),true()),y) -> true() r5: app(app(or(),x),true()) -> true() r6: app(app(or(),false()),false()) -> false() r7: app(app(forall(),p),nil()) -> true() r8: app(app(forall(),p),app(app(cons(),x),xs)) -> app(app(and(),app(p,x)),app(app(forall(),p),xs)) r9: app(app(forsome(),p),nil()) -> false() r10: 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. weighted path order base order: max/plus interpretations on natural numbers: app#_A(x1,x2) = max{0, x2 - 5} app_A(x1,x2) = max{x1 + 7, x2 + 4} forall_A = 3 cons_A = 4 precedence: app# = app = forall = cons partial status: pi(app#) = [] pi(app) = [1, 2] pi(forall) = [] pi(cons) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: app#_A(x1,x2) = 0 app_A(x1,x2) = max{x1 + 2, x2 + 6} forall_A = 3 cons_A = 4 precedence: app# = app = forall = cons partial status: pi(app#) = [] pi(app) = [1, 2] pi(forall) = [] pi(cons) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.