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: Richard is working if and only if Elisabeth is drinking water. Elisabeth is excited if and only if it is cloudy. If Elisabeth drinks water, then Elisabeth is excited. It is cloudy or Richard is working.
If Richard works, then Elisabeth is drinking water can be inferred via the biconditional elimination rule. If Elisabeth were excited, then it is cloudy can be inferred via the biconditional elimination rule. If Elisabeth drinks water, then Richard is working can be inferred via the biconditional elimination rule. If it is cloudy, then Elisabeth is excited can be inferred via the biconditional elimination rule.