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 climbing a mountain if and only if Linda is a politician. It is overcast or David is climbing a mountain. Linda is not a politician.
If David doesn't climb a mountain, then it is overcast can be inferred via the rewriting rule. If David climbs a mountain, then Linda is a politician can be inferred via the biconditional elimination rule. If Linda were a politician, then David is climbing a mountain can be inferred via the biconditional elimination rule. David is not climbing a mountain can be inferred via the biconditional elimination rule.