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 not snowing. It is snowing if and only if Susan is a soldier. Susan is a soldier if and only if Elisabeth is an astronaut. Elisabeth is a carpenter.
It is not snowing and Elisabeth is a carpenter can be inferred via the conjunction rule. Elisabeth is a carpenter and it is not snowing can be inferred via the conjunction rule. If it snows, then Susan is a soldier can be inferred via the biconditional elimination rule. If Susan were a soldier, then Elisabeth is an astronaut can be inferred via the biconditional elimination rule. If Susan were a soldier, then it is snowing can be inferred via the biconditional elimination rule. If Elisabeth were an astronaut, then Susan is a soldier can be inferred via the biconditional elimination rule. Susan is not a soldier can be inferred via the biconditional elimination rule.