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: If it is sunny, then William is a poet. William is a poet if and only if Jessica is playing tennis. Jessica is not playing tennis. If William were a poet, then it is sunny.
It is sunny if and only if William is a poet can be inferred via the biconditional introduction rule. William is a poet if and only if it is sunny can be inferred via the biconditional introduction rule. If William were a poet, then Jessica is playing tennis can be inferred via the biconditional elimination rule. If Jessica plays tennis, then William is a poet can be inferred via the biconditional elimination rule. William is not a poet can be inferred via the biconditional elimination rule.