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Unformatted text preview: A to B . Suppose that g is an injective function from B to A . Prove that f is bijective. 4. (2 points) Let A = { 1 , 2 , 3 , 4 } . A function f from A to A is called nondecreasing if, for all x,y A , if x y , then f ( x ) f ( y ). For example, the following is a nondecreasing function: f (1) = 1 ,f (2) = 3 ,f (3) = 3 ,f (4) = 4 . How many nondecreasing functions are there from A to A ? Justify your answer. (Hint: try a direct counting argument, not a fancy formula!)...
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 Fall '08
 Weissman
 Math

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