Question 1062037
A is a projection map, that is, (x, y, z) ----> (x, y)
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B is an embedding map, that is, (x, y) -----> (x, y, 0)
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AB is the identity map onto R^2, (x, y) ----A--> (x, y, z) ---B--> (x, y)
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We can say that A is the left inverse of B which is equivalent to B is the right inverse of A
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However, the composition BA does not give the identity map
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For example,
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(0, 0, 1)  ----> (0, 0, 0)  ----> (0, 0) for infinitely many z's