[CG] Some beginner questions about Prolog+CG

Hello CG-ers, I am consider Prolog+CG as a tool to author an Interactive Fiction. Iam puzzled by the following Prolog+CG answer.    Universal > Warrior, Weapon.    Warrior > Jedi, Trooper, Machine, Sith.    Weapon > Light_saber, Blaster_gun, Mega_laser.    Machine = Battle_droid, Super_battle_droid, Cyclopedus.    [Machine:Cyclopedus]-       -armed_with->[Mega_laser], -protected_by1->[Machine:Super_battle_droid]-quantity->[Integer = 14],       -protected_by2->[Machine:Battle_droid]-          -quantity->[Integer = 10],          -armed_with->[Blaster_gun]. When requested :    ?- M -quantity-> I. The only answer is :    {M=[Machine : Super_battle_droid], I=[Integer = 14]} Why {M=[Machine : Battle_droid], I=[Integer = 10]} is not another correct answer ? Regards, - damien