Dirichlet approximation theorem

E637303

The Dirichlet approximation theorem is a fundamental result in Diophantine approximation that guarantees, for any real number and positive integer, the existence of a nearby rational number with bounded denominator and small approximation error.

All labels observed (3)

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Statements (41)

Predicate Object
instanceOf mathematical theorem ⓘ
result in Diophantine approximation ⓘ
appearsIn advanced undergraduate number theory courses ⓘ
graduate courses on analytic number theory ⓘ
introductory texts on Diophantine approximation ⓘ
category theorem in analytic number theory ⓘ
concerns approximation of real numbers by rationals ⓘ
bounds on denominators of approximating fractions ⓘ
coreConcept Diophantine inequality ⓘ
fractional parts of multiples of a real number ⓘ
lattice points in the plane ⓘ
ensures existence of p and q with small |qα − p| ⓘ
equivalentFormulation For any real α and positive integer N, there exist integers p and q with 1 ≤ q ≤ N such that |qα − p| < 1/N. ⓘ
errorBound approximation error less than 1/(qN) ⓘ
approximation error less than 1/q² for infinitely many rationals ⓘ
field Diophantine approximation ⓘ
number theory ⓘ
generalizationOf basic rational approximation results from continued fractions ⓘ
guarantees existence of good rational approximations to real numbers ⓘ
hasVersion inhomogeneous approximation form ⓘ
simultaneous approximation for vectors in R^n ⓘ
historicalPeriod 19th century mathematics ⓘ
holdsFor every positive integer N ⓘ
every real number ⓘ
implies existence of infinitely many good rational approximations to any irrational number ⓘ
for any real α there are infinitely many rationals p/q with |α − p/q| < 1/q² ⓘ
influenced development of modern Diophantine approximation theory ⓘ
namedAfter Johann Peter Gustav Lejeune Dirichlet ⓘ
prerequisiteFor Dirichlet's theorem on Diophantine approximation on manifolds (in basic form) ⓘ
provides quantitative bound on rational approximation error ⓘ
relatedTo Hurwitz's theorem ⓘ
linked to: Hurwitz theorem

Kronecker approximation theorem ⓘ
Minkowski's theorem in geometry of numbers ⓘ
Roth's theorem ⓘ
linked to: Roth theorem
statement For any real number α and any positive integer N, there exist integers p and q with 1 ≤ q ≤ N such that |α − p/q| < 1/(qN). ⓘ
strength gives optimal exponent 2 in |α − p/q| < C/q² for general real numbers ⓘ
usedIn geometry of numbers ⓘ
metric Diophantine approximation ⓘ
study of continued fractions ⓘ
uniform distribution theory ⓘ
usesMethod pigeonhole principle ⓘ

How these facts were elicited

Referenced by (4)

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

Diophantine approximation → hasKeyResult → Dirichlet approximation theorem ⓘ
Dirichlet approximation theorem → prerequisiteFor → Dirichlet's theorem on Diophantine approximation on manifolds (in basic form) ⓘ
linked to: Dirichlet approximation theorem
Hurwitz theorem → refines → Dirichlet approximation theorem ⓘ
Roth's theorem → comparesWith → Dirichlet's approximation theorem ⓘ
subject linked to: Roth theorem
linked to: Dirichlet approximation theorem