RiemannXi[s]
gives the Riemann xi function
.
RiemannXi
RiemannXi[s]
gives the Riemann xi function
.
Details
- Mathematical function, suitable for symbolic and numeric manipulations.
.- For certain special arguments, RiemannXi automatically evaluates to exact values.
- RiemannXi is an entire function with no branch cut discontinuities.
- RiemannXi can be evaluated to arbitrary numerical precision.
- RiemannXi automatically threads over lists.
- RiemannXi can be used with Interval and CenteredInterval objects. »
Examples
open all close allBasic Examples (5)
RiemannXi[2.]Plot over a subset of the reals:
Plot[RiemannXi[s], {s, -2, 3}]Plot over a subset of the complexes:
ComplexPlot3D[RiemannXi[z], {z, -10 - 10I, 10 + 10I}, PlotLegends -> Automatic]Series expansion at the origin:
Series[RiemannXi[x], {x, 0, 2}]//FullSimplifySeries expansion at Infinity:
Series[RiemannXi[x], {x, ∞, 2}]//Normal//FullSimplifyScope (26)
Numerical Evaluation (6)
RiemannXi[.5]RiemannXi[-11.]N[RiemannXi[5 / 4], 50]N[RiemannXi[4 / 6], 20]The precision of the output tracks the precision of the input:
RiemannXi[5.21111111111111111111]RiemannXi[.5 + .5I]N[RiemannXi[4 + I]]Evaluate efficiently at high precision:
RiemannXi[2`100]//TimingRiemannXi[12`1000];//TimingCompute worst-case guaranteed intervals using Interval and CenteredInterval objects:
RiemannXi[Interval[{1.1, 1.2 }]]RiemannXi[CenteredInterval[8 + 2I, 1 / 100]]Or compute average-case statistical intervals using Around:
RiemannXi[ Around[2, 0.01]]Compute the elementwise values of an array:
RiemannXi[{{1 / 2, -1}, {0, 1 / 2}}]Or compute the matrix RiemannXi function using MatrixFunction:
MatrixFunction[RiemannXi, {{1 / 2, -1}, {0, 1 / 2}}]//FullSimplifySpecific Values (4)
Simple exact values are generated automatically:
Table[RiemannXi[z ], {z, -2, 1}]RiemannXi[1 / 2]RiemannXi[0]RiemannXi[x]Find the minimum of RiemannXi[x]:
xmin = x /. FindRoot[D[RiemannXi[x], x] == 0, {x, 5}]Plot[RiemannXi[x], {x, -3, 4}, Epilog -> Style[Point[{xmin, RiemannXi[xmin]}], PointSize[Large], Red]]Visualization (2)
Plot the RiemannXi:
Plot[RiemannXi[s], {s, -3, 4}]Plot the real part of the RiemannXi function:
ComplexContourPlot[Re[RiemannXi[z]], {z, -4 - 4I, 4 + 4I}, IconizedObject[«PLotOptions»]]Plot the imaginary part of the RiemannXi function:
ComplexContourPlot[Im[RiemannXi[z]], {z, -4 - 4I, 4 + 4I}, IconizedObject[«PlotOptions»]]Function Properties (6)
RiemannXi has the mirror property
:
FullSimplify[RiemannXi[Conjugate[z]] == Conjugate[RiemannXi[z]]]RiemannXi is defined through the identity:
RiemannXi[s] == 1 / 2 s(s - 1) π^-s / 2 Zeta[s] Gamma[s / 2] //FullSimplifyRiemannXi threads element‐wise over lists:
RiemannXi[{0.5, 1.5, 2.5, 3.5}]RiemannXi is neither non-increasing nor non-decreeing:
FunctionMonotonicity[RiemannXi[x], x]RiemannXi is not an injective function:
FunctionInjective[RiemannXi[x], x]//QuietPlot[{RiemannXi[x], 3 / 4}, {x, -5.5, 6.5}, AxesOrigin -> {0, 0}]TraditionalForm formatting, while avoiding the evaluation:
RiemannXi[s]//HoldForm//TraditionalFormDifferentiation (3)
First derivative with respect to
:
D[RiemannXi[s] , s]//FullSimplifyHigher derivatives with respect to
:
Table[D[RiemannXi[s] , {s, k}], {k, 1, 3}]//FullSimplifyPlot the higher derivatives with respect to
:
Plot[%, {s, -9, 9}, PlotLegends -> {"First Derivative", "Second Derivative", "Third Derivative"}]Formula for the ![]()
derivative with respect to
:
D[RiemannXi[s], {s, k}]// FullSimplifySeries Expansions (5)
Find the Taylor expansion using Series:
Series[RiemannXi[x], {x, 0, 2}]// Normal//FullSimplifyPlots of the first three approximations around
:
terms = Normal@Table[Series[RiemannXi[x], {x, 0, m}], {m, 1, 5, 2}];
Plot[{RiemannXi[x], terms}, {x, -10, 10}]Find the series expansion at Infinity:
Series[RiemannXi[x], {x, Infinity, 1}]// Normal// FullSimplifyFind the series expansion for an arbitrary symbolic direction
:
Series[RiemannXi[x], {x, DirectedInfinity[z], 1}, Assumptions -> x > 0]// FullSimplifyTaylor expansion at a generic point:
Series[RiemannXi[x], {x, x0, 1}]//Normal// FullSimplifySeries expansion at a singular point:
Series[RiemannXi[x], {x, 1, 2}]//Normal//FullSimplifyApplications (2)
Li's criterion states that the Riemann hypothesis is equivalent to the condition
for all positive
:
Subscript[λ, n_Integer] := SeriesCoefficient[D[Log[RiemannXi[(z/z - 1)]], z], {z, 0, n - 1}]Generate and plot the first few values of
:
N[Table[Subscript[λ, n], {n, 1, 10}], 20]ListLinePlot[%]Test the Pustyl’nikov form of the Riemann hypothesis, which states that all the even-order derivatives of the xi function are positive:
Table[N[Derivative[2n][RiemannXi][1 / 2]], {n, 5}]Related Guides
Related Links
Text
Wolfram Research (2014), RiemannXi, Wolfram Language function, https://reference.wolfram.com/language/ref/RiemannXi.html (updated 2022).
CMS
Wolfram Language. 2014. "RiemannXi." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2022. https://reference.wolfram.com/language/ref/RiemannXi.html.
APA
Wolfram Language. (2014). RiemannXi. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/RiemannXi.html
BibTeX
@misc{reference.wolfram_2026_riemannxi, author="Wolfram Research", title="{RiemannXi}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/RiemannXi.html}", note=[Accessed: 13-June-2026]}
BibLaTeX
@online{reference.wolfram_2026_riemannxi, organization={Wolfram Research}, title={RiemannXi}, year={2022}, url={https://reference.wolfram.com/language/ref/RiemannXi.html}, note=[Accessed: 13-June-2026]}