What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one y_4 for which if y_4 were an electrician, then y_4 is a politician. For all y_4, y_4 is a politician if and only if y_4 is an electrician. For all y_4, y_4 will climb a mountain or y_4 is not an electrician. For all y_4, y_4 will not climb a mountain.
For all y_4, if y_4 were an electrician, then y_4 is climbing a mountain. For all y_4, if y_4 were a politician, then y_4 is an electrician. For all y_4, if y_4 were an electrician, then y_4 is a politician.