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: Jennifer is writing a letter if and only if Jessica is reading a book. If Jennifer writes a letter, then Michael is a musician. If Michael were a musician, then Jennifer is writing a letter.
Jennifer is writing a letter if and only if Michael is a musician can be inferred via the biconditional introduction rule. Michael is a musician if and only if Jennifer is writing a letter can be inferred via the biconditional introduction rule. If Jennifer writes a letter, then Jessica is reading a book can be inferred via the biconditional elimination rule. If Jessica reads a book, then Jennifer is writing a letter can be inferred via the biconditional elimination rule.