What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Karen is an artist and Linda is working. David is not writing a letter. Joseph is bored if and only if David is writing a letter.
Karen is an artist. Linda is working. If Joseph were bored, then David is writing a letter. If David writes a letter, then Joseph is bored. Joseph is not bored.