What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is overcast. If Charles were a lawyer, then Elisabeth is sleeping. If Elisabeth sleeps, then Charles is a lawyer. If Charles were a lawyer, then it is not overcast.
Charles is not a lawyer. If Elisabeth sleeps, then it is not overcast. Charles is a lawyer if and only if Elisabeth is sleeping. Elisabeth is sleeping if and only if Charles is a lawyer.