What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all x_8, x_8 will not write a letter or x_8 will play squash. There is at least one x_8 for which if x_8 were a server, then x_8 is sleeping. For all x_8, if x_8 plays squash, then x_8 is a mechanic. For all x_8, if x_8 were a mechanic, then x_8 is a server. For all x_8, x_8 will write a letter or x_8 will take a plane. For all x_8, if x_8 takes a plane, then x_8 is a mechanic.
For all x_8, if x_8 plays squash, then x_8 is a server can be inferred via the universal transitivity rule. For all x_8, if x_8 takes a plane, then x_8 is a server can be inferred via the universal transitivity rule. There is at least one x_8 for which if x_8 were a mechanic, then x_8 is sleeping can be inferred via the existential transitivity rule. For all x_8, x_8 will take a plane or x_8 will play squash can be inferred via the universal resolution rule.