Masur–Veech volumes of Abelian strata
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Numbers
$g$
$\mu$
$c$ 
$V_{g,\mu,c}$
2
2
hyp:
0.8117424252833536436370027724058759270810632139390451807622321615830904621402266349176822269562749379
comment: The exact volume is $\pi^{4}/120$ [1].
2
1, 1
hyp:
0.7215488224740921276773357976941119351831673012791512717886508102960804107913125643712730906277999448
comment: The exact volume is $\pi^{4}/135$ [1].
3
4
hyp:
0.1430638680915631602723540838768481992361930845358700321340887183756092132205878293897650906476065084
comment: The exact volume is $\pi^{6}/6720$ [1].
3
4
odd:
0.3956334129939524432223125282520246497395956905683319407164922582239069600174280713988565469760970108
comment: The exact volume is $\pi^{6}/2430$ [1].
3
3, 1
connected:
0.3617219775944708052318285972589939654762017742339034886550786360904292205873628081360974143781458384
comment: The exact volume is $(16/42525)\pi^{6}$ [1].
3
2, 2
hyp:
0.1017343061984449139714517929790920527901817490032853561842408664004332182901957897882773977938535171
comment: The exact volume is $\pi^{6}/9450$ [1].
3
2, 2
odd:
0.2225437948090982493125507971417638654785225759446867166530268952509476650098032901618568076740545686
comment: The exact volume is $\pi^{6}/4320$ [1].
3
2, 1, 1
connected:
0.2543357654961122849286294824477301319754543725082133904606021660010830457254894744706934944846337926
comment: The exact volume is $\pi^{6}/3780$ [1].
3
1, 1, 1, 1
connected:
0.1978167064969762216111562641260123248697978452841659703582461291119534800087140356994282734880485054
comment: The exact volume is $\pi^{6}/4860$ [1].
4
6
hyp:
0.01634240488603425031540828838718509871840756495198323600796077803796521732706296898429829476517532505
comment: The exact volume is $\pi^{8}/580608$ [1].
4
6
even:
0.1586690143127615746178663092951944636458604706212108674100322295549760715179849978303663771452637189
comment: The exact volume is $(32/1913625)\pi^{8}$ [1].
4
6
odd:
0.2510193390494860848446713096271631163147401976624625050822775506631457381436872035988218075930929928
comment: The exact volume is $\pi^{8}/37800$ [1].
4
5, 1
connected:
0.2581913201651856872688047756165106339237327747385328623703426235392356163763639808445024306671813640
comment: The exact volume is $\pi^{8}/36750$ [1].
4
4, 2
even:
0.08824898638458495170320475729079953307940085074070947444298820140501217356614003251521079173194675527
comment: The exact volume is $\pi^{8}/107520$ [1].
4
4, 2
odd:
0.1195330185949933737355577664891252934832096179345059548010845479348313038779462874280103845681395204
comment: The exact volume is $\pi^{8}/79380$ [1].
4
4, 1, 1
connected:
0.1597924033301126697506588197858098541355406350860583076333942741489932360868379189575833265928254005
comment: The exact volume is $(11/653184)\pi^{8}$ [1].
4
3, 3
hyp:
0.009562641487599469898844621319130023478656769434760476384086763834786504310235702994240830765451161630
comment: The exact volume is $\pi^{8}/992250$ [1].
4
3, 3
nonhyp:
0.1859402511477674702553120812053060120849927390092314852461315190097375838101386693324605982171059206
comment: The exact volume is $\pi^{8}/51030$ [1].
4
3, 2, 1
connected:
0.1338769808263925785838246984678203287011947720866466693772146936870110603432998419193716307163162628
comment: The exact volume is $\pi^{8}/70875$ [1].
4
3, 1, 1, 1
connected:
0.1024737384103251836073719914198130911046182206095320185356458149209220461886986444321116185729828185
comment: The exact volume is $(62/5740875)\pi^{8}$ [1].
4
2, 2, 2
even:
0.05159841969350547299584910253447241835358548507506173715580149652520217950731348073975781600524689296
comment: The exact volume is $(37/6804000)\pi^{8}$ [1].
4
2, 2, 2
odd:
0.06754860686227490130368759200036507470275126846819737549957121589025623161852693846843295169605801021
comment: The exact volume is $(31/4354560)\pi^{8}$ [1].
4
2, 2, 1, 1
connected:
0.09134314837634076976292205989210657843675268303828496712716210871353358804673062130957126887415328348
comment: The exact volume is $(131/13608000)\pi^{8}$ [1].
4
2, 1, 1, 1, 1
connected:
0.06972759418041280134574203045198975453187227712846180696729931962865159392880200099967272433141472022
comment: The exact volume is $\pi^{8}/136080$ [1].
4
1, 1, 1, 1, 1, 1
connected:
0.05310566263841540627746413228363664133033504742915171964984210808081141598213808965025579206655222126
comment: The exact volume is $(377/67359600)\pi^{8}$ [1].
Definition
The Masur–Veech volume $V_{g,\mu,c}$ is the hypersurface measure of the area-one locus in the connected component $c$ of the stratum $\mathcal H(\mu)$ of holomorphic Abelian differentials on compact connected genus-$g$ Riemann surfaces with labelled zeros of orders $\mu$ [1].
Parameters
$g$
—   genus ($g\geq2$)
$\mu$
—   zero profile ($\mu=(m_1,\ldots,m_n)$ is a non-increasing partition of $2g-2$ into positive integers)
$c$
—   connected component (A component allowed by the classification in [2], with the labels defined in Comments)
Formulas
(1)
For $g\geq2$, $\displaystyle V_{g,(2g-2),\mathrm{hyp}}=\frac{2\pi^{2g}}{(2g+1)!}\frac{(2g-3)!!}{(2g-2)!!}$ [4]. The double factorial $k!!$ is the product of positive integers at most $k$ with the same parity as $k$, and $0!!=1$.
(2)
For $g\geq2$, $\displaystyle V_{g,(g-1,g-1),\mathrm{hyp}}=\frac{8\pi^{2g}}{(2g+2)!}\frac{(2g-2)!!}{(2g-1)!!}$ [4].
Comments
(3)
The relative-period lattice $H^1(X,\{z_i\};\mathbb Z\oplus i\mathbb Z)$ has covolume one. All zeros are labelled, including zeros of equal order; sorting their orders does not divide by permutations of labels. There are no poles or extra regular marked points. The area is $A=(i/2)\int_X\omega\wedge\bar\omega$, and the phase of $\omega$ is retained. For $D=2g+n-1$ and $\omega=r\omega_1$ with $A(\omega_1)=1$, the measure is disintegrated as $d\nu=r^{2D-1}dr\,d\nu_1$. Thus the volume used here is $2D$ times the measure of the area-at-most-one cone [1].
(4)
The label hyp denotes the hyperelliptic component; in $\mathcal H(g-1,g-1)$ its hyperelliptic involution interchanges the two zeros. The labels even and odd denote the nonhyperelliptic components with even and odd spin parity, respectively. They exclude the hyperelliptic component even when it has the same spin parity. The label nonhyp denotes the nonhyperelliptic component of $\mathcal H(g-1,g-1)$ for even $g\geq4$, and connected denotes the sole component of any other connected stratum. Both genus-two strata use hyp [2].
(5)
The genus-two volume $V_{2,(2),\mathrm{hyp}}=\pi^4/120$ equals $\zeta(2,2)$.
(6)
For a hyperelliptic component with two zeros, forgetting the two labels divides the volume by $2!$. In particular, the labelled volume of $\mathcal H(1,1)$ is $\pi^4/135$ [3]. The hyperelliptic formulas use the labelled convention of [4], Section 6.5.
Programs
(P1)
Sage
# Download the attached generate.py into the current directory.
from generate import volume
volume(4, (3, 3), 'hyp', digits=100)
(P2)
Sage
# Hyperelliptic components only, with labelled zeros and area one.
# zeros=1: H(2*g-2); zeros=2: H(g-1, g-1). See CMSZ, Section 6.5.
import numberdb.sage as numberdb
from math import factorial, prod
from sage.rings.integer_ring import ZZ
from sage.rings.rational_field import QQ
from sage.rings.real_arb import RealBallField


def hyperelliptic_volume(g, zeros=1, digits=100):
    g = ZZ(g)
    if g < 2 or zeros not in (1, 2):
        raise ValueError('Use genus g >= 2 and one or two zeros.')
    def df(n):
        return prod(range(n, 0, -2))
    if zeros == 1:
        q = QQ(2 * df(2*g - 3)) / (factorial(2*g + 1) * df(2*g - 2))
    else:
        q = QQ(8 * df(2*g - 2)) / (factorial(2*g + 2) * df(2*g - 1))
    field = RealBallField(numberdb.bits(digits, losing=64))
    return field(q) * field.pi()**(2*g)


hyperelliptic_volume(5, zeros=2, digits=100)  # H(4,4), beyond the stored range.
References
[1]
A. Eskin, H. Masur and A. Zorich, Moduli spaces of Abelian differentials: the principal boundary, counting problems, and the Siegel–Veech constants. Publications Mathématiques de l’IHÉS 97 (2003), 61–179. Sections 2.1–2.2 and 5.2; Table 1. (arXiv)
[2]
M. Kontsevich and A. Zorich, Connected components of the moduli spaces of Abelian differentials with prescribed singularities. Inventiones Mathematicae 153 (2003), 631–678. (arXiv) (doi)
[3]
J. S. Athreya, A. Eskin and A. Zorich, with an appendix by J. Chaika, Right-angled billiards and volumes of moduli spaces of quadratic differentials on the complex projective line. Annales Scientifiques de l’École Normale Supérieure 49 (2016), 1311–1386. Theorem 1.1 and Remark 1.2. (arXiv)
[4]
D. Chen, M. Möller, A. Sauvaget and D. Zagier, Masur–Veech volumes and intersection theory on moduli spaces of Abelian differentials. Inventiones Mathematicae 222 (2020), 283–373. Sections 3.1, 6.3 and 6.5. (arXiv) (doi)
Links
Similar tables
Multiple_zeta_values_of_length_2 —   the entry $\zeta(2,2)$ equals the volume of $\mathcal H(2)$ in the labelled EMZ convention
Weil-Petersson_volumes_of_the_moduli_spaces_of_hyperbolic_surfaces —   volumes of moduli spaces of Riemann surfaces for the Weil-Petersson measure
Data properties
Entries are of type: real number
digits: 100 (Unknown key)
Table is complete: no (it holds all 25 components of all 18 positive zero profiles in genera $2\leq g\leq4$, covering minimal, principal and intermediate strata and every component type occurring in this range; the genus cutoff is a practical choice supported by complete low-genus source tables, and genus one is excluded because it requires a marked regular point)
How they were obtained:

The exact rational coefficients of $\pi^{2g}$ are transcribed from [1], Table 1, which uses numbered zeros. Each rational is converted directly to an Arb ball and multiplied by a certified power of $\pi$. A 64-bit working guard beyond the requested 100 significant digits gives a measured minimum of 393 bits of relative accuracy. A separate 512-bit MPFI calculation is contained in the exact uncertainty interval asserted by every written decimal.

more

All 25 coefficients were checked visually against the source table. Twenty-three also agree exactly with the surface-dynamics transcription in its $\zeta(2g)$ normalization; that software cites EMZ, so this is a transcription check rather than an independent derivation. Independent rational generating-series calculations from [4] recover the six minimal-component values, and the hyperelliptic formulas from [3] and [4] recover all six hyperelliptic values, covering nine distinct entries. The principal-stratum saddle-connection ratios for genera two through four agree with EMZ Table 2. The remaining general nonhyperelliptic multizero coefficients are source transcriptions. The generator, argument-selection justification, checks, controls and numerical evidence are attached.