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_6, if x_6 were a server, then x_6 is a scientist. For all x_6, x_6 is a server. There is at least one x_6 for which if x_6 were a scientist, then x_6 is a doctor. For all x_6, if x_6 were a doctor, then x_6 is playing squash.
For all x_6, x_6 is a scientist can be inferred via the universal modus ponens rule. There is at least one x_6 for which if x_6 were a scientist, then x_6 is playing squash can be inferred via the existential transitivity rule. There is at least one x_6 for which if x_6 were a server, then x_6 is a doctor can be inferred via the existential transitivity rule.