Substitutions: {2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. 4$_$13_:family = :Naudts_VanNoten. 4$_$13_:parent = :Guido. 7$_$13_:child = :Guido. 3$_$16_:grandparent = 7$_$13_:parent. 7$_$13_:family = :Naudts_Huybrechs. 7$_$13_:parent = :Pol. }. N3Trace: 13 [:call {:Frank gc:grandfather _1?who1. }]. :alternatives = {{2$_$17_:child gc:grandparent 2$_$17_:grandparent. 2$_$17_:grandparent gc:sex :M. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. }.} :goalList = {{ . } {:Frank gc:grandfather _1?who1. } } [:call {:Frank gc:grandparent 2$_$17_:grandparent. }]. :alternatives = {{3$_$16_:child gc:parent 3$_$16_:parent. 3$_$16_:parent gc:parent 3$_$16_:grandparent. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. }.} :goalList = {{2$_$17_:child gc:grandparent 2$_$17_:grandparent. } {2$_$17_:grandparent gc:sex :M. } } [:call {:Frank gc:parent 3$_$16_:parent. }]. :alternatives = {{4$_$13_:child gc:childIn 4$_$13_:family. 4$_$13_:parent gc:spouseIn 4$_$13_:family. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. }.} :goalList = {{3$_$16_:child gc:parent 3$_$16_:parent. } {3$_$16_:parent gc:parent 3$_$16_:grandparent. } {2$_$17_:grandparent gc:sex :M. } } [:call {:Frank gc:childIn 4$_$13_:family. }]. :alternatives = {{:Frank gc:childIn :Naudts_VanNoten. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. 4$_$13_:family = :Naudts_VanNoten. }.} :goalList = {{4$_$13_:child gc:childIn 4$_$13_:family. } {4$_$13_:parent gc:spouseIn 4$_$13_:family. } {3$_$16_:parent gc:parent 3$_$16_:grandparent. } {2$_$17_:grandparent gc:sex :M. } } [:call {4$_$13_:parent gc:spouseIn :Naudts_VanNoten. }]. :alternatives = {{:Guido gc:spouseIn :Naudts_VanNoten. } {:Christine gc:spouseIn :Naudts_VanNoten. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. 4$_$13_:family = :Naudts_VanNoten. 4$_$13_:parent = :Guido. 4$_$13_:parent = :Christine. }.} :goalList = {{:Frank gc:childIn :Naudts_VanNoten. } {4$_$13_:parent gc:spouseIn 4$_$13_:family. } {3$_$16_:parent gc:parent 3$_$16_:grandparent. } {2$_$17_:grandparent gc:sex :M. } } [:call {:Guido gc:parent 3$_$16_:grandparent. }]. :alternatives = {{7$_$13_:child gc:childIn 7$_$13_:family. 7$_$13_:parent gc:spouseIn 7$_$13_:family. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. 4$_$13_:family = :Naudts_VanNoten. 4$_$13_:parent = :Guido. 7$_$13_:child = :Guido. 3$_$16_:grandparent = 7$_$13_:parent. }.} :goalList = {{:Guido gc:spouseIn :Naudts_VanNoten. } {3$_$16_:parent gc:parent 3$_$16_:grandparent. } {2$_$17_:grandparent gc:sex :M. } } [:call {:Guido gc:childIn 7$_$13_:family. }]. :alternatives = {{:Guido gc:childIn :Naudts_Huybrechs. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. 4$_$13_:family = :Naudts_VanNoten. 4$_$13_:parent = :Guido. 7$_$13_:child = :Guido. 3$_$16_:grandparent = 7$_$13_:parent. 7$_$13_:family = :Naudts_Huybrechs. }.} :goalList = {{7$_$13_:child gc:childIn 7$_$13_:family. } {7$_$13_:parent gc:spouseIn 7$_$13_:family. } {2$_$17_:grandparent gc:sex :M. } } [:call {7$_$13_:parent gc:spouseIn :Naudts_Huybrechs. }]. :alternatives = {{:Martha gc:spouseIn :Naudts_Huybrechs. } {:Pol gc:spouseIn :Naudts_Huybrechs. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. 4$_$13_:family = :Naudts_VanNoten. 4$_$13_:parent = :Guido. 7$_$13_:child = :Guido. 3$_$16_:grandparent = 7$_$13_:parent. 7$_$13_:family = :Naudts_Huybrechs. 7$_$13_:parent = :Martha. 7$_$13_:parent = :Pol. }.} :goalList = {{:Guido gc:childIn :Naudts_Huybrechs. } {7$_$13_:parent gc:spouseIn 7$_$13_:family. } {2$_$17_:grandparent gc:sex :M. } } [:failed {:Martha gc:sex :M. }]. [:call {:Pol gc:sex :M. }]. :alternatives = {{:Pol gc:sex :M. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. 4$_$13_:family = :Naudts_VanNoten. 4$_$13_:parent = :Guido. 7$_$13_:child = :Guido. 3$_$16_:grandparent = 7$_$13_:parent. 7$_$13_:family = :Naudts_Huybrechs. 7$_$13_:parent = :Pol. }.} :goalList = {{:Pol gc:spouseIn :Naudts_Huybrechs. } {2$_$17_:grandparent gc:sex :M. } } {:solution = {2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. 4$_$13_:family = :Naudts_VanNoten. 4$_$13_:parent = :Guido. 7$_$13_:child = :Guido. 3$_$16_:grandparent = 7$_$13_:parent. 7$_$13_:family = :Naudts_Huybrechs. 7$_$13_:parent = :Pol. }.}. [:call {:Christine gc:parent 3$_$16_:grandparent. }]. :alternatives = {{6$_$13_:child gc:childIn 6$_$13_:family. 6$_$13_:parent gc:spouseIn 6$_$13_:family. } } :subtitutions = {{2$_$17_:child = :Frank. _1?who1 = 2$_$17_:grandparent. 3$_$16_:child = :Frank. 2$_$17_:grandparent = 3$_$16_:grandparent. 4$_$13_:child = :Frank. 3$_$16_:parent = 4$_$13_:parent. 4$_$13_:family = :Naudts_VanNoten. 4$_$13_:parent = :Christine. 6$_$13_:child = :Christine. 3$_$16_:grandparent = 6$_$13_:parent. }.} :goalList = {{:Christine gc:spouseIn :Naudts_VanNoten. } {3$_$16_:parent gc:parent 3$_$16_:grandparent. } {2$_$17_:grandparent gc:sex :M. } } [:failed {:Christine gc:childIn 6$_$13_:family. }]. Query: {:Frank gc:grandfather _1?who1. } Solution: {:Frank gc:grandfather :Pol. }