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Unformatted text preview: the above relationship between equivalent Haskell functions, and orderings which for example behave like the less than ordering between natural numbers. We will also describe natural ways of constructing new relations from old, including those used in relational databases. 2 Sets Our starting point will be the idea of a set, a concept that we shall not formally deFne. Instead, we shall simply use the intuitive idea that a set is a collection of objects. D EFINITION 2.1 (I NFORMAL ) A set is a collection of objects (or individuals) taken from a pool of objects. The objects in a set are also called the elements , or members , of the set. A set is said to contain its elements. We write x A when object x is a member of set A . When x is not a member of A , we write x A or sometimes ( x A ) using notation from the logic course. 3...
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 Spring '09
 Koskesh
 Math, Addition

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