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 x_13, if x_13 were a lawyer, then x_13 is sleeping. For all x_13, if x_13 sleeps, then x_13 is happy. For all x_13, if x_13 were a sailor, then x_13 is happy. Some lawyers will work.
For all x_13, if x_13 were a lawyer, then x_13 is happy can be inferred via the universal transitivity rule. There is at least one x_13 for which x_13 is a lawyer can be inferred via the existential simplification rule. There is at least one x_13 for which x_13 will work can be inferred via the existential simplification rule.