What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Robert makes tea, then it is windy. Robert is making tea if and only if it is windy. If it is windy, then Robert is making tea.
Robert is making tea if and only if it is windy. It is windy if and only if Robert is making tea. If Robert makes tea, then it is windy. If it is windy, then Robert is making tea.