Nilpotency-forcing number: Difference between revisions

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==Definition==
==Definition==


===Symbol-free definition===
A natural number <math>n</math> is said to be '''nilpotency-forcing''' or '''nilpotence-forcing''' if the following equivalent conditions hold:


A natural number is said to be nilpotence-forcing if the following equivalent conditions hold:
# Every group of order <math>n</math> is [[nilpotent group|nilpotent]]
# Every group of order <math>n</math> is a direct product of its Sylow subgroups
# Every prime divisor of <math>n</math> is [[Sylow-direct prime divisor|Sylow-direct]]
# Every prime divisor of <math>n</math> is [[Sylow-unique prime divisor|Sylow-unique]]
# Suppose <math>p_i, p_j</math> are prime divisors of <math>n</math> and <math>p_j^{k_j}</math> is the largest power of <math>p_j</math> dividing <math>n</math>. Then, the order of <math>p_j</math> modulo <math>p_i</math> exceeds <math>k_j</math>. In other words, <math>p_i</math> does not divide <math>p^j^l - 1</math> for <math>1 \le l \le k_j</math>.


* Every group of that order is [[nilpotent group|nilpotent]]
For proof of the equivalence of definitions, see [[classification of nilpotency-forcing numbers]].
* Every group of that order is a direct product of its Sylow subgroups
* Every prime divisor of that number is [[Sylow-direct prime divisor|Sylow-direct]]
* Every prime divisor of that number is [[Sylow-unique prime divisor|Sylow-unique]]


==Relation with other properties==
==Relation with other properties==

Revision as of 20:17, 20 June 2016

This article defines a property that can be evaluated for natural numbers


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Definition

A natural number n is said to be nilpotency-forcing or nilpotence-forcing if the following equivalent conditions hold:

  1. Every group of order n is nilpotent
  2. Every group of order n is a direct product of its Sylow subgroups
  3. Every prime divisor of n is Sylow-direct
  4. Every prime divisor of n is Sylow-unique
  5. Suppose pi,pj are prime divisors of n and pjkj is the largest power of pj dividing n. Then, the order of pj modulo pi exceeds kj. In other words, pi does not divide pjl1 for 1lkj.

For proof of the equivalence of definitions, see classification of nilpotency-forcing numbers.

Relation with other properties

Stronger properties

Weaker properties