Kronecker Symbol Calculator

(a/n) for all integers

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About Kronecker Symbol Calculator

A Kronecker symbol calculator computing (a/n) for any integers a, n. Extends Jacobi symbol to even n and negative n. Zero, negative, and composite moduli are all handled. Used in quadratic form theory and discriminant analysis. Client-side.

Kronecker Symbol Calculator Features

  • (a/n) computation
  • All integers
  • Jacobi extension
  • Table
  • Quadratic forms
Kronecker symbol (a/n): extends Jacobi/Legendre to all integers. For odd positive n: same as Jacobi. For n=2: (a/2)=0 if a even, 1 if a≡±1(mod 8), −1 if a≡±3(mod 8). For n=−1: (a/−1)=−1 if a<0, 1 if a≥0. For n=0: (a/0)=1 if |a|=1, else 0.

How to Use

Enter a and n:

  • (a/n): 0, 1, or −1
  • Decomposition: Product formula
  • Table: For range of values

Extensions

Legendre (a/p) for odd prime p → Jacobi (a/n) for odd positive n → Kronecker (a/n) for ALL integers n. Each step relaxes restrictions on the bottom. Kronecker handles n=0, negative n, even n.

Quadratic Forms

For discriminant D of a quadratic form, (D/n) determines representation: can n = ax²+bxy+cy² with discriminant D? The Kronecker symbol is the natural character for quadratic forms over Z.

Step-by-Step Instructions

  1. 1Enter a.
  2. 2Enter n.
  3. 3Compute (a/n).
  4. 4See decomposition.
  5. 5View table.

Kronecker Symbol Calculator — Frequently Asked Questions

How does Kronecker extend Jacobi?+

Jacobi requires odd positive n. Kronecker defines (a/2) using a mod 8, (a/−1) using sign of a, and (a/0). Then (a/n) = (a/u)·(a/p₁)·...·(a/pₖ) where n=u·p₁·...·pₖ with u being the unit part.

When is (a/n)=0?+

(a/n)=0 when gcd(a,n)>1 (for n≠0 and |a|≠1). For (a/0): equals 1 if |a|=1, else 0. This extends the Legendre convention where (a/p)=0 when p|a.

What's the connection to quadratic reciprocity?+

Quadratic reciprocity generalizes: for the Kronecker symbol, there's a reciprocity law involving the signs and 2-parts of a and n. This extended reciprocity is crucial in algebraic number theory and class field theory.

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