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 it is sunny, then Robert is sleeping. For all x, if x makes tea, then x is sleeping. For all x, if x sleeps, then x is making tea. It is sunny or Robert is making tea.
If Robert were a soldier, then it is sunny can be inferred via the rewriting rule. For all x, x will make tea if and only if x will sleep can be inferred via the universal biconditional introduction rule. For all x, x will sleep if and only if x will make tea can be inferred via the universal biconditional introduction rule.