Consider the following premises. David is happy or Joseph is not taking a plane. For all x_12, x_12 is happy if and only if x_12 is an electrician. Can we infer the following from them? The fact that Joseph takes a plane does not imply that David is an electrician.
 From the fact that for all x_12, x_12 is happy if and only if x_12 is an electrician we can infer that David is happy if and only if David is an electrician. From the fact that David is happy if and only if David is an electrician we can infer that if David were happy, then David is an electrician. From the fact that David is happy or Joseph is not taking a plane we can infer that if Joseph takes a plane, then David is happy. Finally, from the fact that if Joseph takes a plane, then David is happy, and that if David were happy, then David is an electrician we can infer that if Joseph takes a plane, then David is an electrician, which contradicts that The fact that Joseph takes a plane does not imply that David is an electrician. Therefore, the answer is no.