YES *** Computating Strongly Quasi-Reducible Parts *** TRS: [ +(0,0) -> 0, +(s(0),?y) -> s(+(0,?y)), +(?x,s(?y)) -> s(+(?y,?x)), s(s(?x)) -> ?x ] Constructors: {0,s} Defined function symbols: {+} Constructor subsystem: [ s(s(?x)) -> ?x ] Rule part & Conj Part: [ s(s(?x)) -> ?x, +(0,0) -> 0, +(s(0),?y) -> s(+(0,?y)), +(?x,s(?y)) -> s(+(?y,?x)) ] [ ] *** Ground Confluence Check by Rewriting Induction *** Sort: {Nat} Signature: [ + : Nat,Nat -> Nat, s : Nat -> Nat, 0 : Nat ] Rule Part: [ s(s(?x)) -> ?x, +(0,0) -> 0, +(s(0),?y) -> s(+(0,?y)), +(?x,s(?y)) -> s(+(?y,?x)) ] Conjecture Part: [ ] Precedence (by weight): {(+,3),(0,1),(s,0)} Rule part is not confluent. Check ground confluence of Rule part (R0) by basic RI. Rules: [ s(s(?x)) -> ?x, +(0,0) -> 0, +(s(0),?y) -> s(+(0,?y)), +(?x,s(?y)) -> s(+(?y,?x)) ] Conjectures: [ +(0,?y_2) = +(?y_2,0), +(?x_2,?x) = s(+(s(?x),?x_2)) ] STEP 0 ES: [ +(0,?y_2) = +(?y_2,0), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS: [ ] ES0: [ +(0,?y_2) = +(?y_2,0), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS0: [ ] ES1: [ +(0,?y_2) = +(?y_2,0), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS1: [ ] Expand +(0,?y_2) = +(?y_2,0) [ 0 = +(0,0), s(+(?y_3,0)) = +(s(?y_3),0), +(0,?x_8) = +(s(s(?x_8)),0) ] ES2: [ 0 = +(0,0), s(+(?y_3,0)) = +(s(?y_3),0), +(0,?x_8) = +(s(s(?x_8)),0), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS2: [ +(0,?y_2) -> +(?y_2,0) ] STEP 1 ES: [ 0 = +(0,0), s(+(?y_3,0)) = +(s(?y_3),0), +(0,?x_8) = +(s(s(?x_8)),0), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS: [ +(0,?y_2) -> +(?y_2,0) ] ES0: [ 0 = 0, s(+(?y_3,0)) = +(s(?y_3),0), +(0,?x_8) = +(?x_8,0), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS0: [ +(0,?y_2) -> +(?y_2,0) ] ES1: [ s(+(?y_3,0)) = +(s(?y_3),0), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS1: [ +(0,?y_2) -> +(?y_2,0) ] Expand +(s(?y_3),0) = s(+(?y_3,0)) [ s(+(0,0)) = s(+(0,0)), +(?x_5,0) = s(+(s(?x_5),0)) ] ES2: [ s(0) = s(+(0,0)), +(?x_5,0) = s(+(s(?x_5),0)), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS2: [ +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] STEP 2 ES: [ s(0) = s(+(0,0)), +(?x_5,0) = s(+(s(?x_5),0)), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS: [ +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] ES0: [ s(0) = s(0), +(?x_5,0) = +(?x_5,0), +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS0: [ +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] ES1: [ +(?x_2,?x) = s(+(s(?x),?x_2)) ] HS1: [ +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] Expand s(+(s(?x),?x_2)) = +(?x_2,?x) [ s(s(+(0,?y_4))) = +(?y_4,0), s(s(+(?y_5,s(?x)))) = +(s(?y_5),?x), s(+(?x_7,?x_6)) = +(?x_6,s(?x_7)), s(+(s(?x),?x_10)) = +(s(s(?x_10)),?x) ] ES2: [ +(0,?y_4) = +(?y_4,0), s(+(?x,?y_5)) = +(s(?y_5),?x), s(+(?x_7,?x_6)) = +(?x_6,s(?x_7)), s(+(s(?x),?x_10)) = +(s(s(?x_10)),?x) ] HS2: [ s(+(s(?x),?x_2)) -> +(?x_2,?x), +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] STEP 3 ES: [ +(0,?y_4) = +(?y_4,0), s(+(?x,?y_5)) = +(s(?y_5),?x), s(+(?x_7,?x_6)) = +(?x_6,s(?x_7)), s(+(s(?x),?x_10)) = +(s(s(?x_10)),?x) ] HS: [ s(+(s(?x),?x_2)) -> +(?x_2,?x), +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] ES0: [ +(0,?y_4) = +(?y_4,0), s(+(?x,?y_5)) = +(s(?y_5),?x), s(+(?x_7,?x_6)) = s(+(?x_7,?x_6)), +(?x_10,?x) = +(?x_10,?x) ] HS0: [ s(+(s(?x),?x_2)) -> +(?x_2,?x), +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] ES1: [ s(+(?x,?y_5)) = +(s(?y_5),?x) ] HS1: [ s(+(s(?x),?x_2)) -> +(?x_2,?x), +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] Expand +(s(?y_5),?x) = s(+(?x,?y_5)) [ s(+(0,?y_7)) = s(+(?y_7,0)), s(+(?y_8,s(?y_5))) = s(+(s(?y_8),?y_5)), +(?x_10,?x_9) = s(+(?x_9,s(?x_10))), +(s(?y_5),?x_13) = s(+(s(s(?x_13)),?y_5)) ] ES2: [ s(+(0,?y_7)) = s(+(?y_7,0)), +(?y_5,?y_8) = s(+(s(?y_8),?y_5)), +(?x_10,?x_9) = s(+(?x_9,s(?x_10))), +(s(?y_5),?x_13) = s(+(s(s(?x_13)),?y_5)) ] HS2: [ +(s(?y_5),?x) -> s(+(?x,?y_5)), s(+(s(?x),?x_2)) -> +(?x_2,?x), +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] STEP 4 ES: [ s(+(0,?y_7)) = s(+(?y_7,0)), +(?y_5,?y_8) = s(+(s(?y_8),?y_5)), +(?x_10,?x_9) = s(+(?x_9,s(?x_10))), +(s(?y_5),?x_13) = s(+(s(s(?x_13)),?y_5)) ] HS: [ +(s(?y_5),?x) -> s(+(?x,?y_5)), s(+(s(?x),?x_2)) -> +(?x_2,?x), +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] ES0: [ s(+(0,?y_7)) = s(+(?y_7,0)), +(?y_5,?y_8) = +(?y_5,?y_8), +(?x_10,?x_9) = +(?x_10,?x_9), s(+(?x_13,?y_5)) = s(+(?x_13,?y_5)) ] HS0: [ +(s(?y_5),?x) -> s(+(?x,?y_5)), s(+(s(?x),?x_2)) -> +(?x_2,?x), +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] ES1: [ ] HS1: [ +(s(?y_5),?x) -> s(+(?x,?y_5)), s(+(s(?x),?x_2)) -> +(?x_2,?x), +(s(?y_3),0) -> s(+(?y_3,0)), +(0,?y_2) -> +(?y_2,0) ] R0 is ground confluent. Conjucture part is empty. examples/additions/plus10.trs: Success(GCR) (16 msec.)