Gauss's Lemma
Let the multiples 
, 
, ..., 
of an Integer such that 
be taken. If there are an Evennumber 
of least Positive Residues mod 
of these numbers 
, then is aQuadratic Residue of . If is Odd, is a Quadratic Nonresidue. Gauss'slemma can therefore be stated as 
, where 
is the Legendre Symbol. It was proved byGauß 
as a step along the way to the Quadratic Reciprocity Theorem.
- Reflexible Map
- Reflexive Closure
- Reflexive Graph
- Reflexive Reduction
- Reflexive Relation
- Reflexivity
- Region
- Regression
- Regression Coefficient
- Regula Falsi
- Regular Function
- Regular Graph
- Regular Isotopy
- Regular Isotopy Invariant
- Regularity Theorem
- Regularized Beta Function
- Regularized Gamma Function
- Regular Local Ring
- Regular Number
- Regular Parameterization
- Regular Patch
- Regular Point
- Regular Polygon
- Regular Polyhedron
- Regular Prime