# Tutorial - Groups HT23, III and IV

> Source: https://ollybritton.com/notes/uni/prelims/ht23/groups/tutorials/sheets-iii-and-iv/ · Updated: 2023-05-08 · Tags: uni, notes

- [Course - Groups and Group Actions HT23](https://ollybritton.com/notes/uni/prelims/ht23/groups/)

### Flashcards
Let $H, K \leqslant G$ be subgroups. When will $HK$ be a subgroup?::
When $H$ or $K$ is normal.

### Proofs

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