scholarly journals Hyperbolic structures for Artin-Tits groups of spherical type

Author(s):  
Matthieu Calvez ◽  
Bert Wiest
Author(s):  
Benson Farb ◽  
Dan Margalit

This chapter focuses on the metric geometry of Teichmüller space. It first explains how one can think of Teich(Sɡ) as the space of complex structures on Sɡ. To this end, the chapter defines quasiconformal maps between surfaces and presents a solution to the resulting Teichmüller's extremal problem. It also considers the correspondence between complex structures and hyperbolic structures, along with the Teichmüller mapping, Teichmüller metric, and the proof of Teichmüller's uniqueness and existence theorems. The fundamental connection between Teichmüller's theorems, holomorphic quadratic differentials, and measured foliations is discussed as well. Finally, the chapter describes the Grötzsch's problem, whose solution is tied to the proof of Teichmüller's uniqueness theorem.


2021 ◽  
Vol 112 (1) ◽  
Author(s):  
E. Molnár ◽  
I. Prok ◽  
J. Szirmai

AbstractIn connection with our works in Molnár (On isometries of space forms. Colloquia Math Soc János Bolyai 56 (1989). Differential geometry and its applications, Eger (Hungary), North-Holland Co., Amsterdam, 1992), Molnár (Acta Math Hung 59(1–2):175–216, 1992), Molnár (Beiträge zur Algebra und Geometrie 38/2:261–288, 1997) and Molnár et al. (in: Prékopa, Molnár (eds) Non-Euclidean geometries, János Bolyai memorial volume mathematics and its applications, Springer, Berlin, 2006), Molnár et al. (Symmetry Cult Sci 22(3–4):435–459, 2011) our computer program (Prok in Period Polytech Ser Mech Eng 36(3–4):299–316, 1992) found 5079 equivariance classes for combinatorial face pairings of the double-simplex. From this list we have chosen those 7 classes which can form charts for hyperbolic manifolds by double-simplices with ideal vertices. In such a way we have obtained the orientable manifold of Thurston (The geometry and topology of 3-manifolds (Lecture notes), Princeton University, Princeton, 1978), that of Fomenko–Matveev–Weeks (Fomenko and Matveev in Uspehi Mat Nauk 43:5–22, 1988; Weeks in Hyperbolic structures on three-manifolds. Ph.D. dissertation, Princeton, 1985) and a nonorientable manifold $$M_{c^2}$$ M c 2 with double simplex $${\widetilde{{\mathcal {D}}}}_1$$ D ~ 1 , seemingly known by Adams (J Lond Math Soc (2) 38:555–565, 1988), Adams and Sherman (Discret Comput Geom 6:135–153, 1991), Francis (Three-manifolds obtainable from two and three tetrahedra. Master Thesis, William College, 1987) as a 2-cusped one. This last one is represented for us in 5 non-equivariant double-simplex pairings. In this paper we are going to determine the possible Dehn type surgeries of $$M_{c^2}={\widetilde{{\mathcal {D}}}}_1$$ M c 2 = D ~ 1 , leading to compact hyperbolic cone manifolds and multiple tilings, especially orbifolds (simple tilings) with new fundamental domain to $${\widetilde{{\mathcal {D}}}}_1$$ D ~ 1 . Except the starting regular ideal double simplex, we do not get further surgery manifold. We compute volumes for starting examples and limit cases by Lobachevsky method. Our procedure will be illustrated by surgeries of the simpler analogue, the Gieseking manifold (1912) on the base of our previous work (Molnár et al. in Publ Math Debr, 2020), leading to new compact cone manifolds and orbifolds as well. Our new graphic analysis and tables inform you about more details. This paper is partly a survey discussing as new results on Gieseking manifold and on $$M_{c^2}$$ M c 2 as well, their cone manifolds and orbifolds which were partly published in Molnár et al. (Novi Sad J Math 29(3):187–197, 1999) and Molnár et al. (in: Karáné, Sachs, Schipp (eds) Proceedings of “Internationale Tagung über geometrie, algebra und analysis”, Strommer Gyula Nemzeti Emlékkonferencia, Balatonfüred-Budapest, Hungary, 1999), updated now to Memory of Professor Gyula Strommer. Our intention is to illustrate interactions of Algebra, Analysis and Geometry via algorithmic and computational methods in a classical field of Geometry and of Mathematics, in general.


2019 ◽  
Vol 352 ◽  
pp. 572-610 ◽  
Author(s):  
María Cumplido ◽  
Volker Gebhardt ◽  
Juan González-Meneses ◽  
Bert Wiest

During the course of some work on Dewar vessels, which was carried out by one of us (B. L.) and S. F. Gates for the Oxygen Research Committee, a curious anomaly was noticed in the behaviour of an all-metal Dewar vessel. This was a commercial copper vessel of the usual spherical type with a long narrow neck of an alloy of low heat-conductivity; its capacity was two litres. The rate of evaporation of liquid oxygen stored in this vessel was approximately double that of liquid oxygen stored in a silvered glass flask of like capacity; but, when equal weights of hot water were put into each of the vessels, it was found that the rate of cooling of the water in the copper vessel was actually slower than in the silvered glass vessel. It appeared, then, that the copper vessel was only half as efficient as a silvered glass one of like capacity for the storage of liquid oxygen, whereas its efficiency for the storage of hot water was greater than that of the silvered glass vessel. This investigation arose out of a desire to explain the apparent anomaly. Previou work on the factors which influence the efficiency of Dewar vessels has been carried out by Dewar ('Proc. Roy. Inst.,' 1898, p. 815), Banneitz, Rhein and Kurze ('Ann. d. Phys.,' 1920, vol. 61, p. 113), and Briggs ('Proc. Roy. Soc. Edin.,' 1920, vol. 51, p. 97). These investigations have dealt with the efficiency of Dewar vessels considered only as containers for liquid air or oxygen, and the above-mentioned anomaly has therefore not been noticed. Briggs ( loc. cit .) worked with vessels with the vacuum-adjacent surfaces of polished gilding metal (95 per cent. copper). From his results on the rates of evaporation of liquid oxygen from these vessels, he calculated a value for the emissivity of the polished surfaces which was considerably greater than that anticipated from the usually accepted value for copper. This observation is intimately connected with that of Lambert and Gates and will be referred to later.


2021 ◽  
Vol 8 (1) ◽  
pp. 83-92
Author(s):  
Carlos M. C. Riveros ◽  
Cid D. F. Machado

Sign in / Sign up

Export Citation Format

Share Document