YES Problem 1: Infeasibility Problem: [(VAR vNonEmpty x y vNonEmpty x) (STRATEGY CONTEXTSENSITIVE (+ 1 2) (0) (a) (fSNonEmpty) (s 1) ) (RULES +(0,x) -> x +(s(x),y) -> s(+(x,y)) ) ] Infeasibility Conditions: +(x,a) ->* 0 Problem 1: Obtaining a model using Mace4: -> Usable Rules: +(0,x) -> x +(s(x),y) -> s(+(x,y)) -> Mace4 Output: ============================== Mace4 ================================= Mace4 (64) version 2009-11A, November 2009. Process 3368123 was started by sandbox on z018.star.cs.uiowa.edu, Tue Jul 30 09:35:24 2024 The command was "./mace4 -c -f /tmp/mace43368110-2.in". ============================== end of head =========================== ============================== INPUT ================================= % Reading from file /tmp/mace43368110-2.in assign(max_seconds,100). formulas(assumptions). ->(x1,y) -> ->(+(x1,x2),+(y,x2)) # label(congruence). ->(x2,y) -> ->(+(x1,x2),+(x1,y)) # label(congruence). ->(x1,y) -> ->(s(x1),s(y)) # label(congruence). ->(+(0,x1),x1) # label(replacement). ->(+(s(x1),x2),s(+(x1,x2))) # label(replacement). ->*(x,x) # label(reflexivity). ->(x,y) & ->*(y,z) -> ->*(x,z) # label(transitivity). end_of_list. formulas(goals). (exists x4 ->*(+(x4,a),0)) # label(goal). end_of_list. ============================== end of input ========================== ============================== PROCESS NON-CLAUSAL FORMULAS ========== % Formulas that are not ordinary clauses: 1 ->(x1,y) -> ->(+(x1,x2),+(y,x2)) # label(congruence) # label(non_clause). [assumption]. 2 ->(x2,y) -> ->(+(x1,x2),+(x1,y)) # label(congruence) # label(non_clause). [assumption]. 3 ->(x1,y) -> ->(s(x1),s(y)) # label(congruence) # label(non_clause). [assumption]. 4 ->(x,y) & ->*(y,z) -> ->*(x,z) # label(transitivity) # label(non_clause). [assumption]. 5 (exists x4 ->*(+(x4,a),0)) # label(goal) # label(non_clause) # label(goal). [goal]. ============================== end of process non-clausal formulas === ============================== CLAUSES FOR SEARCH ==================== formulas(mace4_clauses). -->(x,y) | ->(+(x,z),+(y,z)) # label(congruence). -->(x,y) | ->(+(z,x),+(z,y)) # label(congruence). -->(x,y) | ->(s(x),s(y)) # label(congruence). ->(+(0,x),x) # label(replacement). ->(+(s(x),y),s(+(x,y))) # label(replacement). ->*(x,x) # label(reflexivity). -->(x,y) | -->*(y,z) | ->*(x,z) # label(transitivity). -->*(+(x,a),0) # label(goal). end_of_list. ============================== end of clauses for search ============= % There are no natural numbers in the input. ============================== DOMAIN SIZE 2 ========================= ============================== MODEL ================================= interpretation( 2, [number=1, seconds=0], [ function(0, [ 0 ]), function(a, [ 1 ]), function(s(_), [ 0, 1 ]), function(+(_,_), [ 0, 1, 0, 1 ]), relation(->*(_,_), [ 1, 0, 0, 1 ]), relation(->(_,_), [ 1, 0, 0, 1 ]) ]). ============================== end of model ========================== ============================== STATISTICS ============================ For domain size 2. Current CPU time: 0.00 seconds (total CPU time: 0.01 seconds). Ground clauses: seen=38, kept=34. Selections=5, assignments=6, propagations=14, current_models=1. Rewrite_terms=79, rewrite_bools=51, indexes=21. Rules_from_neg_clauses=5, cross_offs=5. ============================== end of statistics ===================== User_CPU=0.01, System_CPU=0.00, Wall_clock=0. Exiting with 1 model. Process 3368123 exit (max_models) Tue Jul 30 09:35:24 2024 The process finished Tue Jul 30 09:35:24 2024 Mace4 cooked interpretation: % number = 1 % seconds = 0 % Interpretation of size 2 0 = 0. a = 1. s(0) = 0. s(1) = 1. +(0,0) = 0. +(0,1) = 1. +(1,0) = 0. +(1,1) = 1. ->*(0,0). - ->*(0,1). - ->*(1,0). ->*(1,1). ->(0,0). - ->(0,1). - ->(1,0). ->(1,1). The problem is infeasible.