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, x_6 is an office clerk. For all x_6, if x_6 plays squash, then x_6 is a poet. There is at least one x_6 for which if x_6 were an office clerk, then x_6 is a poet. For all x_6, if x_6 were a poet, then x_6 is playing squash.
There is at least one x_6 for which x_6 is a poet can be inferred via the existential modus ponens rule. There is at least one x_6 for which if x_6 were an office clerk, then x_6 is playing squash can be inferred via the existential transitivity rule. For all x_6, x_6 will play squash if and only if x_6 is a poet can be inferred via the universal biconditional introduction rule. For all x_6, x_6 is a poet if and only if x_6 will play squash can be inferred via the universal biconditional introduction rule.