Dirichlet theorem on Fourier series
E898518
The Dirichlet theorem on Fourier series gives conditions under which a periodic function can be represented by a convergent Fourier series, specifying how and where the series converges to the function.
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
mathematical theorem
ⓘ
result in Fourier analysis ⓘ |
| appliesTo |
2π-periodic functions
ⓘ
periodic functions of real variable ⓘ |
| assumes |
discontinuities are finite (no infinite jumps)
ⓘ
function has a finite number of discontinuities on a period ⓘ function has a finite number of maxima and minima on a period ⓘ function is 2π-periodic ⓘ |
| clarifies |
behavior of Fourier series at discontinuities
ⓘ
conditions for convergence of Fourier series ⓘ |
| concerns |
pointwise convergence of Fourier series
ⓘ
representation of periodic functions by trigonometric series ⓘ |
| concludes |
Fourier series converges at each point of continuity
ⓘ
Fourier series converges at each point of discontinuity to the midpoint of the left and right limits ⓘ Fourier series converges to (f(x+0)+f(x-0))/2 at jump discontinuities ⓘ Fourier series converges to f(x) where f is continuous ⓘ |
| doesNotGuarantee |
absolute convergence of Fourier series
ⓘ
uniform convergence ⓘ |
| field |
Fourier analysis
NERFINISHED
ⓘ
harmonic analysis ⓘ mathematical analysis ⓘ |
| givesConditionOn |
piecewise continuously differentiable functions
ⓘ
piecewise monotone functions ⓘ piecewise smooth functions ⓘ |
| hasApplicationIn |
heat equation
ⓘ
partial differential equations ⓘ signal processing ⓘ vibrating string problem ⓘ |
| historicalPeriod | 19th century ⓘ |
| implies |
Fourier series of a function of bounded variation converges at every point
ⓘ
Fourier series of a function of bounded variation converges to the average of one-sided limits at each point ⓘ Fourier series of a piecewise smooth periodic function converges everywhere ⓘ Fourier series represents the function almost everywhere under its hypotheses ⓘ |
| isTaughtIn |
Fourier analysis courses
ⓘ
advanced calculus courses ⓘ real analysis courses ⓘ |
| namedAfter | Johann Peter Gustav Lejeune Dirichlet NERFINISHED ⓘ |
| oftenStatedFor | functions of bounded variation ⓘ |
| relatedTo |
Dirichlet kernel
NERFINISHED
ⓘ
Gibbs phenomenon NERFINISHED ⓘ pointwise convergence of trigonometric series ⓘ uniform convergence of Fourier series ⓘ |
| strongerThan | basic convergence results for continuous periodic functions with piecewise continuous derivative ⓘ |
| typeOfConvergence | pointwise convergence ⓘ |
| uses | Dirichlet kernel NERFINISHED ⓘ |
| weakerThan |
Carleson theorem on almost everywhere convergence of Fourier series
NERFINISHED
ⓘ
results assuming higher smoothness such as C^1 or C^2 periodic functions ⓘ |
Referenced by (1)
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