Abstract Algebra: Theory and Applications · Problem 6.5.12

Introduction to Cryptography — Thomas Judson

Mathematics — Abstract Algebra · cosets-lagrange-theorem

Problem

If ghg−1∈Hghg^{-1} \in H for all g∈Gg \in G and h∈Hh \in H, show that right cosets are identical to left cosets. That is, show that gH=HggH = Hg for all g∈Gg \in G. Hint. Let g1∈gHg_1 \in gH. Show that g1∈Hgg_1 \in Hg and thus gH⊂HggH \subset Hg.

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