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: It is windy if and only if Mary is reading a book. Mary is not curious. For all x_21, x_21 is curious if and only if x_21 will read a book. Susan is climbing a mountain if and only if it is windy.
If it is windy, then Mary is reading a book can be inferred via the biconditional elimination rule. If Susan climbs a mountain, then it is windy can be inferred via the biconditional elimination rule. If Mary reads a book, then it is windy can be inferred via the biconditional elimination rule. If it is windy, then Susan is climbing a mountain can be inferred via the biconditional elimination rule. For all x_21, if x_21 were curious, then x_21 is reading a book can be inferred via the universal biconditional elimination rule. For all x_21, if x_21 reads a book, then x_21 is curious can be inferred via the universal biconditional elimination rule.