What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z_4, z_4 is a scientist if and only if z_4 will play tennis. Joseph is not fast. Richard is playing tennis if and only if Joseph is fast.
If Richard plays tennis, then Joseph is fast. If Joseph were fast, then Richard is playing tennis. Richard is not playing tennis. For all z_4, if z_4 were a scientist, then z_4 is playing tennis. For all z_4, if z_4 plays tennis, then z_4 is a scientist.