Main example: the subsets of a set form a Boolean algebra. To see why, let's define a set and its power set , which is the set of all subsets of . We can then define two operations on , union () and intersection (), as well as a complement operation () that takes the complement of a set with respect to .
Formally, we can define the Boolean algebra as the tuple . We can then verify that these operations satisfy the axioms of a Boolean algebra:
Commutativity of and :
Associativity of and :
Distributivity of over and over :
Identity elements:
Complement:
Double complement:
This Boolean algebra formalize the usual Logic, with intersection and union in the place of "and" and "or", and the subsets being "propositions".
In the context of sets, the "implies" operator corresponds to set inclusion. That is, if and are sets, then means that if an element is in , then it must also be in . Symbolically, is equivalent to . Alternatively, we can also define as the set of all elements that are either not in or that are in both and . Symbolically, , where is the complement of (that is, the set of all elements not in ).
But even more, what in Logic is considered a "verifiable proposition" can be understood as open sets, endowing in this way to the set with a topology. See this answer or this other and this blog entry. Maybe ideas in the blog post are related to new logic for Quantum Mechanics.