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: David is not a politician. If Mary listens to a song, then Jessica is an artist. William is happy if and only if David is a politician. If Jessica were an artist, then William is happy.
If Mary listens to a song, then William is happy can be inferred via the transitivity rule. If William were happy, then David is a politician can be inferred via the biconditional elimination rule. If David were a politician, then William is happy can be inferred via the biconditional elimination rule. William is not happy can be inferred via the biconditional elimination rule.