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: Sarah is a carpenter or it is late. Elisabeth is not working. Sarah is a carpenter if and only if Elisabeth is working. Susan is not a soldier or Robert is sleeping.
If Sarah were a carpenter, then Elisabeth is working can be inferred via the biconditional elimination rule. If Elisabeth works, then Sarah is a carpenter can be inferred via the biconditional elimination rule. Sarah is not a carpenter can be inferred via the biconditional elimination rule.