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 Susan listens to a song, then John is a scientist. Robert is rich if and only if John is a scientist. If Robert were rich, then Susan is listening to a song.
If Robert were rich, then John is a scientist can be inferred via the transitivity rule. If Robert were rich, then John is a scientist can be inferred via the biconditional elimination rule. If John were a scientist, then Robert is rich can be inferred via the biconditional elimination rule.