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_8, x_8 is a taxi driver. There is at least one x_8 for which x_8 will write a letter and x_8 will climb a mountain.
There is at least one x_8 for which x_8 will write a letter can be inferred via the existential simplification rule. There is at least one x_8 for which x_8 will climb a mountain can be inferred via the existential simplification rule.