What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y, y is a carpenter if and only if y is a taxi driver. If Thomas were sad, then Karen is a taxi driver. Karen is a carpenter or Thomas is sad.
For all y, if y were a carpenter, then y is a taxi driver. For all y, if y were a taxi driver, then y is a carpenter.