1. Consider the set Z of integers, and let R denote the subset all multiples of 4. Define addition as ordinary addition in Z, and define multiplication * in R by a*b = ab/4(adsbygoogle = window.adsbygoogle || []).push({});

a. Show that (R, +, *) is a ring with unity (what is the unity of R?)

b. Show that the mapping Ø: R → Z defined by Ø(x) = x/4 is an isomorphism

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# Addition in R

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