Ivan Shishkin, Oak Grove

Quotient of a group and subgroup

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Consider a group GG and a normal subgroup HH.
Is it necessarily the case that the quotient group G/HG/H is isomorphic to a subgroup of GG?

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Solution by Ancient Tree

0 useful votes

No, it is not necessarily the case. For example, with G=ZG=\mathbb{Z}, the subgroups of GG are of the form nZn\Z; but the quotients Z/nZ\Z /n\Z are not of this form since they are finite.

For a counter-example in the finite groups, it's a bit less trivial.