Some Results with Kernels
Published:
This is part 1 of a three-part series, written in my junior year of high school, that works up to proving that (Z/pZ)× is cyclic: the multiplicative group of integers mod a prime has a generator. I was teaching myself group theory at the time and worked out the route on my own, so the proofs are mine rather than the textbook’s.
This part proves that every finite abelian group splits as a direct product of its p-parts, using kernels of the maps x ↦ xpk.
Part 3 ends with an interactive version you can play with: watch (Z/pZ)× turn out cyclic.
