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: It is overcast if and only if Elisabeth is a poet. Elisabeth is not a poet. For all z, z will play squash.
If it is overcast, then Elisabeth is a poet can be inferred via the biconditional elimination rule. If Elisabeth were a poet, then it is overcast can be inferred via the biconditional elimination rule. It is not overcast can be inferred via the biconditional elimination rule.