Hello everyone, An example from a homework assignment has me stymied. There are two parts. Here they are: First part: Let M(x,y) be "x has sent y an e-mail message" and T(x,y) be "x has telephoned y," where the domain consists of all students in your class. Use quantifiers to express each of these statements. (Assume that all e-mail messages that were sent are received, which is not the way things often work.) And the statement I'm having problems with: There is a student in your class who has not received an e-mail message from anyone else in the class and who has not been called by any other student in the class. Here is the answer from the book: ∃x∀y(x≠y → (¬M(x,y) ∧ ¬T(y,x))) I agree with everything except for the order of x and y after M. Why isn't it like this: ∃x∀y(x≠y → (¬M(y,x) ∧ ¬T(y,x))) After all, since M(x,y) = x has sent y an email message and T(x,y) = x has telephoned y it seems that y should come before x in both instances in the answer. Could someone please clarify this for me. Thanks.