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: max/plus interpretations on natural numbers: app#_A(x1,x2) = max{2, x1, x2 + 1} app_A(x1,x2) = max{x1, x2 + 1} forall_A = 3 cons_A = 0 forsome_A = 2 The next rules are strictly ordered: p1 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(forsome(),p),app(app(cons(),x),xs)) -> app#(p,x) p3: 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} {p3} -- 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) p2: app#(app(forsome(),p),app(app(cons(),x),xs)) -> app#(p,x) 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: max/plus interpretations on natural numbers: app#_A(x1,x2) = x1 app_A(x1,x2) = x2 + 1 forsome_A = 4 cons_A = 3 The next rules are strictly ordered: p2 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) 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} -- 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: max/plus interpretations on natural numbers: app#_A(x1,x2) = x2 + 2 app_A(x1,x2) = max{x1 + 2, x2 + 3} forsome_A = 0 cons_A = 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: max/plus interpretations on natural numbers: app#_A(x1,x2) = x2 + 3 app_A(x1,x2) = max{x1, x2 + 3} forall_A = 1 cons_A = 0 The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.