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: For all y, y is a doctor. For all y, y is a mechanic or y will not drink water. There is at least one y for which if y were a doctor, then y is a mechanic.
There is at least one y for which y is a mechanic can be inferred via the existential modus ponens rule. For all y, if y drinks water, then y is a mechanic can be inferred via the universal rewriting rule.