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 were an astronaut, then Patricia is running. If it is cloudy, then Patricia is running. Susan is drinking water if and only if it is cloudy. If Patricia goes running, then it is cloudy.
If Robert were an astronaut, then it is cloudy can be inferred via the transitivity rule. It is cloudy if and only if Patricia is running can be inferred via the biconditional introduction rule. Patricia is running if and only if it is cloudy can be inferred via the biconditional introduction rule. If Susan drinks water, then it is cloudy can be inferred via the biconditional elimination rule. If it is cloudy, then Susan is drinking water can be inferred via the biconditional elimination rule.