Mahler measure
introduction
- for a Laurent polynomial $P(x_1,\cdots, x_n)\in \mathbb{Z}[x_1^{\pm 1},\cdots,x_n^{\pm 1}]$, the (logarithmic) Mahler measure is defined to be
$$ \begin{aligned} m(P):&=\int_{0}^{1}\cdots \int_{0}^{1} \ln |P(e^{2\pi i \theta_1},\cdots, e^{2\pi i \theta_n})|\, d\theta_1\cdots d\theta_n\\ &= \frac{1}{(2\pi i)^n}\int_{|x_1|=\dots=|x_n|=1} \log|P(x_1,\dots,x_n)| \; \frac{dx_1}{x_1} \dots \frac{dx_n}{x_n} \end{aligned} $$
monic polynomial
- For a monic polynomial in one variable $P \in \mathbb{C}[x]$ one can compute $m(P)$ by Jensen's formula
$$ \frac{1}{2\pi i}\int_{|x|=1} \log|P(x)| \; \frac{dx}{x} = \sum_{\alpha:P(\alpha)=0} \max(0,\log|\alpha|)\,, $$
- but no explicit formula is known for polynomials in several variables.
example
- $m(1 + x - x^3 - x^4 - x^5 - x^6 - x^7 + x^9 + x^{10})=0.1623576120\cdots$
- $m(x^3-x-1)=0.28119957432\cdots$
- $m(x^3+x+1)=0.382245085840\cdots$
Multivariate Mahler measure
Smyth
- thm [Smith1981]
$$ m(1+x_1+x_2)=L_{-3}'(-1)=\frac{3\sqrt{3}}{4\pi}L_{-3}(2)=0.3230659472\cdots $$
$$ m(1+x_1+x_2+x_3)=14\zeta'(-2)=\frac{7}{2\pi^2}\zeta(3)=0.4262783988\cdots $$
Rodriguez-Villegas
- conjecture
$$ m(1+x_1+x_2+x_3+x_4)=-L_{f}'(-1)=\frac{675\sqrt{15}}{16\pi^5}L_{f}(4)=0.5444125617\cdots $$
$$ m(1+x_1+x_2+x_3+x_4+x_5)=-8L_{g}'(-1)=\frac{648}{\pi^6}L_{g}(5)=0.6273170748\cdots $$ where $$ f(\tau)=\eta(3\tau)^3\eta(5\tau)^3+\eta(\tau)^3\eta(15\tau)^3 $$ and $$ g(\tau)=\eta(\tau)^2\eta(2\tau)^2\eta(3\tau)^2\eta(6\tau)^2 $$
- Boyd conjecture on Mahler measure of three variables polynomial
- Mahler measures and L-values of elliptic curves
- Mahler measure and dilogarithm
computational resource
- https://docs.google.com/file/d/0B8XXo8Tve1cxSTAxSnVRUmpEeFU/edit
- http://mathworld.wolfram.com/LehmersMahlerMeasureProblem.html
- http://mathworld.wolfram.com/MahlerMeasure.html
encyclopedia
expositions
- Bertin, Marie-José, and MATILDE LALÍN. Mahler Measure of Multivariable Polynomials Women in Numbers 2: Research Directions in Number Theory 606 (2013): 125.
- Smyth, Chris. 2008. “The Mahler Measure of Algebraic Numbers: a Survey.” In Number Theory and Polynomials, 352:322–349. London Math. Soc. Lecture Note Ser. Cambridge: Cambridge Univ. Press. http://www.maths.ed.ac.uk/~chris/Smyth240707.pdf http://arxiv.org/pdf/math/0701397.pdf
- Lalin Mahler measures as values of regulators 2006
- Finch, Modular Forms on $SL_2(\mathbb{Z})$ 2005
- The many aspects of Mahler's measure, Banff workshop, 2003
- Lalin Introduction to Mahler measure, 2003
- Boyd, Mahler's measure, hyperbolic geometry and the dilogarithm 2002
lecture notes
- Course at Harvard University Spring 2002.
- Fernando Rodriguez Villegashttp://www.ma.utexas.edu/users/villegas/KL/
- Suggested exercises on periods.
- The following are class notes taken by Sam Vandervelde (samv@mandelbrot.org).
- Notes 1
- Notes 2
- Notes 3
- Notes 4
- Notes 5
- The following are class notes taken by Matilde Lalin (mlalin@math.harvard.edu).
- Notes 6
articles
- Cochrane, Todd, R. M. S. Dissanayake, Nicholas Donohoue, M. I. M. Ishak, Vincent Pigno, Chris Pinner, and Craig Spencer. ‘Minimal Mahler Measure in Real Quadratic Fields’. arXiv:1410.4482 [math], 16 October 2014. http://arxiv.org/abs/1410.4482.
- Erdelyi, Tamas. “The Mahler Measure of the Rudin-Shapiro Polynomials.” arXiv:1406.2233 [math], June 9, 2014. http://arxiv.org/abs/1406.2233.
- Zudilin, Wadim. 2013. “Regulator of Modular Units and Mahler Measures”. ArXiv e-print 1304.3869. http://arxiv.org/abs/1304.3869.
- A dynamical interpretation of the global canonical height on an elliptic curve
- Mahler's Measure and the Dilogarithm (I)
- Mahler's Measure and the Dilogarithm (II)
- Authors: David W. Boyd, Fernando Rodriguez-Villegas, Nathan M. Dunfield
- C. J. Smyth, An explicit formula for the Mahler measure of a family of 3-variable polynomials, J. Th. Nombres Bordeaux 14 (2002), 683{700
- Boyd, David W. 1998. “Mahler’s Measure and Special Values of $L$-Functions.” Experimental Mathematics 7 (1): 37–82.
- Deninger, Christopher. Deligne periods of mixed motives, K-theory and the entropy of certain Zn-actions Journal of the American Mathematical Society 10.2 (1997): 259-282.
- [Smith1981] Smyth, C. J. 1981. “On Measures of Polynomials in Several Variables.” Bulletin of the Australian Mathematical Society 23 (1): 49–63. doi:http://dx.doi.org/10.1017/S0004972700006894.