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 y, y will sleep if and only if y is a writer. Robert is not sleeping. For all y, y will sleep if and only if y is a writer.
For all y, if y sleeps, then y is a writer can be inferred via the universal biconditional elimination rule. For all y, if y sleeps, then y is a writer can be inferred via the universal biconditional elimination rule. For all y, if y were a writer, then y is sleeping can be inferred via the universal biconditional elimination rule. For all y, if y were a writer, then y is sleeping can be inferred via the universal biconditional elimination rule.