Skip to content
START WITH A QUESTION

What would you like to understand?

Find an answer. See the moment it becomes clear. Follow the idea further.

← Concept directory

Answers for “为什么正规子群满足 gH = Hg?”

4 keyword matches

Understanding your question. You can explore the search results below now.

Understand why

↗

A normal subgroup satisfies gH=HggH = Hg because its defining property is that it is invariant under conjugation, meaning gHg−1=HgHg^{-1} = H. By right-multiplying both sides of this equation by gg, the g−1g^{-1} and gg cancel out, yielding the equality of the left coset gHgH and the right coset HgHg.

Conditions: H is a normal subgroup of G; g is an element of the group G

Meet the concept

↗

A normal subgroup (also called an invariant subgroup) is a subgroup H of a group G such that all conjugates of every element in H belong to H. Algebraically, this condition is expressed as gHg−1=HgHg^{-1} = H for any element gg in G.

Conditions: H is a subgroup of G; The condition must hold for all elements in H; The condition must hold for all elements g in G

Meet the concept

↗

In the context of group theory, gHgH represents the left coset of the subgroup H with respect to the element g, while HgHg represents the right coset of H with respect to g. For a normal subgroup, these two sets are identical.

Conditions: H is a subgroup of G; g is an element of the group G

Find a method

↗

We can traverse all elements of a group G by constructing cosets using a subgroup H. By multiplying every element g in G with the subgroup H (forming left cosets gH or right cosets Hg), the union of all distinct cosets covers every element of G exactly once.

Conditions: G is a group; H is a subgroup of G