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 were a cashier, then Robert is a server. If Richard were happy, then it is windy. Richard is happy or Susan is a cashier. It is windy if and only if Robert is a server.
If it is windy, then Robert is a server can be inferred via the biconditional elimination rule. If Robert were a server, then it is windy can be inferred via the biconditional elimination rule.