title: Periodicity
text: # Periodicity
  
  Periodicity or periodic may refer to:
  
  ## Mathematics
  
  * Bott periodicity theorem, addresses Bott periodicity: a modulo-8 recurrence relation in the homotopy groups of classical groups
  * Periodic function, a function whose output contains values that repeat periodically
  * Periodic mapping
  
  ## Physical sciences
  
  * Periodic table of chemical elements
  * Periodic trends, relative characteristics of chemical elements observed
  * Redshift periodicity, astronomical term for redshift quantization
  
  ## Other uses
  
  * Fokker periodicity blocks, which mathematically relate musical intervals
  * Periodic acid, a compound of iodine
  * Principle of periodicity, a concept in generally accepted accounting principles
  * Quasiperiodicity, property of a system that displays irregular periodicity
  