On the maximum of the Moebius invariant in the four disjoint domain problem
Dalʹnevostočnyj matematičeskij žurnal, Tome 10 (2010) no. 1, pp. 41-49.

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Let $r(D,a)$ denote the conformal radius of the domain $D$ with respect to the point $a$. In this paper we obtain the supremum of the product $$ \prod_{k=1}^{4}\frac{r(D_{k},a_{k})}{|a_{k+1}-a_{k}|}, \quad a_{5}:=a_{1} $$ for all simply connected disjoint domains $D_{k}\subset\overline{\mathbb{C}}$ and points $a_{k}\in D_{k},k=1,\ldots,4$. Using the method of interior variations due to M. Schiffer we establish the form of quadratic differential associated with extremal partition problem $\prod\limits_{k=1}^{n}r(D_{k},a_{k})|a_{k+1}-a_{k}|^{-1}\to\sup$ for arbitrary $n\geqslant 3$. For $n=4$ we studed the circle domains and their boundaries for the corresponding quadratic differential.
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D. A. Kirillova. On the maximum of the Moebius invariant in the four disjoint domain problem. Dalʹnevostočnyj matematičeskij žurnal, Tome 10 (2010) no. 1, pp. 41-49. http://geodesic.mathdoc.fr/item/DVMG_2010_10_1_a4/

[1] G. M. Goluzin, Geometricheskaya teoriya funktsii kompleksnogo premennogo, Nauka, M., 1966, 628 pp. | MR | Zbl

[2] V. N. Dubinin, “Simmetrizatsiya v geometricheskoi teorii funktsii kompleksnogo peremennogo”, Uspekhi matematicheskikh nauk, 49:1 (1994), 3–76 | MR | Zbl

[3] G. V. Kuzmina, “Metody geometricheskoi teorii funktsii I, II”, Algebra i analiz, 9:3 (1997), 41–103 (5, 1–50) ; 5, 1–50 | MR | Zbl | MR | Zbl

[4] M. A. Lavrentev, “K teorii konformnykh otobrazhenii”, Trudy fiz. mat. in-ta im. V. A. Steklova, 5, 1934, 159–245 | Zbl

[5] A. K. Bakhtin, G. P. Bakhtina, Yu. B. Zelinskii, Topologo-algebraicheskie struktury i geometricheskie metody v kompleksnom analize, 73, In-t matematiki NAN Ukraïni, 2008, 308 pp. | MR | Zbl

[6] G. V. Kuzmina, “K zadache o maksimume proizvedeniya konformnykh radiusov nenalegayuschikh oblastei”, Zap. nauchn. semin. LOMI, 100, 1980, 131–145 | MR | Zbl

[7] S. I. Fedorov, “O maksimume odnogo konformnogo invarianta v zadache o nenalegayuschikh oblastyakh”, Zap. nauchn. semin. LOMI, 112, 1981, 172–183 | MR | Zbl

[8] A. K. Bakhtin, “Kusochno-razdelyayuschee preobrazovanie i ekstremalnye zadachi so svobodnymi polyusami”, Doklady RAN, 405:2 (2005), 151–153 | MR | Zbl

[9] V. N. Dubinin, D. A. Kirillova, “K zadacham ob ekstremalnom razbienii”, Zap. nauchn. semin. POMI, 357, 2008, 54–74 | MR

[10] G. V. Kuzmina, Moduli semeistv krivykh i kvadratichnye differentsialy, Trudy Matem. in-ta im. V. A. Steklova, 139, 1980, 241 pp. | MR | Zbl