YES a__U11ttNmarkNa__U21ttMNsa__plusmarkNmarkMa__U31tt0a__U41ttMNa__plusa__xmarkNmarkMmarkNa__andttXmarkXa__isNat0tta__isNatplusV1V2a__anda__isNatV1isNatV2a__isNatsV1a__isNatV1a__isNatxV1V2a__anda__isNatV1isNatV2a__plusN0a__U11a__isNatNNa__plusNsMa__U21a__anda__isNatMisNatNMNa__xN0a__U31a__isNatNa__xNsMa__U41a__anda__isNatMisNatNMNmarkU11X1X2a__U11markX1X2markU21X1X2X3a__U21markX1X2X3markplusX1X2a__plusmarkX1markX2markU31Xa__U31markXmarkU41X1X2X3a__U41markX1X2X3markxX1X2a__xmarkX1markX2markandX1X2a__andmarkX1X2markisNatXa__isNatXmarkttttmarksXsmarkXmark00a__U11X1X2U11X1X2a__U21X1X2X3U21X1X2X3a__plusX1X2plusX1X2a__U31XU31Xa__U41X1X2X3U41X1X2X3a__xX1X2xX1X2a__andX1X2andX1X2a__isNatXisNatX2.1a__U1120tt03a__U2132s11a__plus22003a__U4134a__x24a__and21plus22x24U1120U2132U4134and21a__U11212tt0mark11a__U213231s11a__plus221a__U311100a__U413231a__x221a__and212a__isNat11plus221isNat11x221U11212U213231U3111U413231and212a__U31tt0a__isNat0ttmarkU11X1X2a__U11markX1X2markU21X1X2X3a__U21markX1X2X3markplusX1X2a__plusmarkX1markX2markU31Xa__U31markXmarkU41X1X2X3a__U41markX1X2X3markxX1X2a__xmarkX1markX2markandX1X2a__andmarkX1X2markisNatXa__isNatXmarkttttmarksXsmarkXmark00a__U11X1X2U11X1X2a__U21X1X2X3U21X1X2X3a__plusX1X2plusX1X2a__U31XU31Xa__U41X1X2X3U41X1X2X3a__xX1X2xX1X2a__andX1X2andX1X2a__isNatXisNatX1tt0520001a__U311131a__isNat1101mark1190U31191isNat181s1181U11210a__U11220U21330a__U21340plus2140a__plus2150U413110a__U413120x260a__x270and2160a__and2170AProVEAProVE Commit ID: 48fb2092695e11cc9f56e44b17a92a5f88ffb256 marcel 20180622 unpublished dirty Statistics for single proof: 100.00 % (3 real / 0 unknown / 0 assumptions / 3 total proof steps)http://aprove.informatik.rwth-aachen.deJohnDoe