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: It is snowing if and only if it is cold. If Michael were a politician, then Elisabeth is an electrician. Michael is a politician. If Susan plays a game, then it is cold. Susan is playing a game or Thomas is sad. If Thomas were sad, then it is cold.
Elisabeth is an electrician can be inferred via the modus ponens rule. It is cold can be inferred via the disjunction elimination rule. If it snows, then it is cold can be inferred via the biconditional elimination rule. If it is cold, then it is snowing can be inferred via the biconditional elimination rule.