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 Robert plays squash, then Richard is playing tennis. If it is windy, then Charles is a server. If Charles were a server, then Robert is playing squash. If Richard plays tennis, then it is windy.
If Robert plays squash, then it is windy can be inferred via the transitivity rule. If it is windy, then Robert is playing squash can be inferred via the transitivity rule. If Charles were a server, then Richard is playing tennis can be inferred via the transitivity rule. If Richard plays tennis, then Charles is a server can be inferred via the transitivity rule.