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 it is cold, then Richard is climbing a mountain. Richard is climbing a mountain if and only if it is late.
If Richard climbs a mountain, then it is late can be inferred via the biconditional elimination rule. If it is late, then Richard is climbing a mountain can be inferred via the biconditional elimination rule.