What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: If Jessica plays tennis, then it is late. If Barbara were excited, then Elisabeth is working. Elisabeth is not working. Jessica is playing tennis. If Patricia were a writer, then Barbara is excited.
It is late can be inferred via the modus ponens rule. Barbara is not excited can be inferred via the modus tollens rule. If Patricia were a writer, then Elisabeth is working can be inferred via the transitivity rule. Elisabeth is not working and Jessica is playing tennis can be inferred via the conjunction rule. Jessica is playing tennis and Elisabeth is not working can be inferred via the conjunction rule.