What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one x_7 for which if x_7 plays tennis, then x_7 is sad. For all x_7, if x_7 were a sailor, then x_7 is playing tennis. For all x_7, x_7 will write a letter or x_7 is a sailor. For all x_7, x_7 will not write a letter.
There is at least one x_7 for which if x_7 were a sailor, then x_7 is sad. For all x_7, x_7 is a sailor.