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: If David works, then it is windy. Patricia is an astronaut. If Karen plays tennis, then it is windy. David is working if and only if Patricia is an astronaut.
If David works, then Patricia is an astronaut can be inferred via the biconditional elimination rule. If Patricia were an astronaut, then David is working can be inferred via the biconditional elimination rule.