301.7H Extra: All Groups of Prime and Double-Prime Order

Lagrange's theorem is such a powerful tool that it can tell us what ALL possible groups of certain orders must be, up to isomorphism. Here we prove that every group of prime order is cyclic, and every group of double-prime order is either cyclic or dihedral.

[PunmasterSTP]

Double-prime? More like "Definitely the right time"...to learn some group theory! 👍

[TTFMjock]

4:56. Doesn’t this assume that a non-cyclic group of order 2-P exists? The proof bring really IF such a group exists THEN it must be iso to Dp.

Of course it might be trivial to prove that a dihedral Dp can be constructed from any order 2p

[speedbird]

Hi Matthew, would you please suggest some good vidoes about master's level algebra lessons.
Your videos about undergrad degree algebra are really outstanding.

[Lyblix]

Hello! Why couldn’t we also fill in 4’s row, since it can be written as 2p. Thank you!