Euler criterion

E662761

Euler criterion is a number-theoretic result that characterizes quadratic residues modulo an odd prime using exponentiation, providing a practical way to evaluate the Legendre symbol.

All labels observed (1)

Label Occurrences
Euler criterion canonical 1

How this entity was disambiguated

Statements (43)

Predicate Object
instanceOf number-theoretic result ⓘ
theorem in number theory ⓘ
appliesTo integer a relatively prime to p ⓘ
odd prime p ⓘ
assumes gcd(a,p)=1 ⓘ
p is an odd prime ⓘ
category results on quadratic residues ⓘ
theorems about prime moduli ⓘ
characterizes quadratic non-residues modulo an odd prime ⓘ
quadratic residues modulo an odd prime ⓘ
dependsOn Fermat's little theorem for its proof ⓘ
properties of the multiplicative group modulo a prime ⓘ
doesNotApplyTo composite moduli ⓘ
equivalentTo (a/p) ≡ a^((p-1)/2) (mod p) where (a/p) is the Legendre symbol ⓘ
field number theory ⓘ
hasConsequence exactly half of the nonzero residues modulo an odd prime are quadratic residues ⓘ
the Legendre symbol takes values in {−1,1} for a not divisible by p ⓘ
linked to: Legendre symbol
historicalPeriod 18th century mathematics ⓘ
holdsIn finite field of order p ⓘ
implies the Legendre symbol is a multiplicative character of order 2 ⓘ
involvesConcept Fermat's little theorem ⓘ
Legendre symbol ⓘ
modular arithmetic ⓘ
modular exponentiation ⓘ
multiplicative group modulo p ⓘ
odd prime ⓘ
quadratic non-residue ⓘ
quadratic residue ⓘ
logicalForm if and only if statement ⓘ
namedAfter Leonhard Euler ⓘ
provides practical method to compute the Legendre symbol ⓘ
relatedTo Gauss's law of quadratic reciprocity ⓘ
Jacobi symbol ⓘ
multiplicative characters modulo p ⓘ
statement For an odd prime p and integer a with gcd(a,p)=1, a is a quadratic non-residue modulo p if and only if a^((p-1)/2) ≡ -1 (mod p). ⓘ
For an odd prime p and integer a with gcd(a,p)=1, a is a quadratic residue modulo p if and only if a^((p-1)/2) ≡ 1 (mod p). ⓘ
subfield elementary number theory ⓘ
typeOf criterion for quadratic residuosity ⓘ
usedFor evaluating the Legendre symbol ⓘ
testing whether an integer is a quadratic residue modulo an odd prime ⓘ
usedIn algorithms in computational number theory ⓘ
primality testing methods ⓘ
proofs involving quadratic residues ⓘ

How these facts were elicited

Referenced by (1)

Full triples — surface form annotated when it differs from this entity's canonical label.

Legendre symbol → computableBy → Euler criterion ⓘ