Section 2.2: Problem 10 Solution
Working problems is a crucial part of learning mathematics. No one can learn... merely by poring over the definitions, theorems, and examples that are worked out in the text. One must work part of it out for oneself. To provide that opportunity is the purpose of the exercises.
James R. Munkres
Show that Here is a two-place predicate symbol and is a constant symbol.
iff for every such that , iff for every such that and for every , iff for every such that and for every , iff for every , iff for every , iff .