What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Mary works, then James is an artist. Mary is working or Robert is making tea. If James were an artist, then it is overcast. If Robert makes tea, then James is an artist. If it is overcast, then Jessica is taking a plane.
If Mary works, then it is overcast. If James were an artist, then Jessica is taking a plane. If Robert makes tea, then it is overcast. James is an artist.