##  [Quadratic Nonresidue](/quadratic-nonresidue) 

  ##  [Quadratic Nonresidue](https://puremath.quantumdictionary.io/quadratic-nonresidue-0) 

  

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- Mathematics & Logic -

**Pure Mathematics Dictionary**

 







 

 

 

 



 

 

 

 

Definition

An integer r (or its congruence class modulo n) that is not congruent to any square modulo n; equivalently r is outside the image of the squaring map x ↦ x^2 on Z/nZ.