Abstract Algebra: Theory and Applications · Problem 9.4.8

Normal Subgroups and Factor Groups — Thomas Judson

Mathematics — Abstract Algebra · isomorphism-proof-or-disproof

Problem

Prove that Q\mathbb{Q} is not isomorphic to Z\mathbb{Z}. Hint. Assume that Q\mathbb{Q} is cyclic and try to find a generator.

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