Cosets, Subgroup Index and Finite-Group Divisibility
Handbook guide to cosets, subgroup index and finite-group divisibility, covering definitions, key results, methods, verification checks and worked examples.
Every page in the KEVOS library tagged index. 8 pages.
Handbook guide to cosets, subgroup index and finite-group divisibility, covering definitions, key results, methods, verification checks and worked examples.
Handbook treatment of subgroup tests, direct products, coset partitions and the divisibility relation between subgroup and group orders.
The discriminant of a basis, the field discriminant, and the index-squared relation that governs maximal order computation.
Primes that divide the index for every choice of defining polynomial, why they exist, and what they force computationally.
The norm of an ideal as its index in the order, its multiplicativity, and its use as a size measure and consistency check.
Orders as subrings that are full-rank lattices, the equation order, the maximal order, and the index that separates them.
Decomposing a prime that does not divide the index, by factoring the defining polynomial modulo that prime.
A cheap modular test deciding whether an order is maximal at a given prime, without computing the maximal order.