Groups defined by extended affine Lie algebras with nullity 2 (Q2372708)

From the text: In 1990, \textit{R. J. Høegh-Krohn} and \textit{B. S. Torresani} [J. Funct. Anal. 89, No. 1, 106--136 (1990; Zbl 0792.17019)] introduced a new generalization of affine Lie algebras, called quasi-simple Lie algebras. Later, in 1997, \textit{B. N. Allison, S. Azam, S. Berman, Y. Gao} and \textit{A. Pianzola} [Extended affine Lie algebras and their root systems. Mem. Am. Math. Soc. 126, No. 603 (1997; Zbl 0879.17012)] arranged and developed the theory of these Lie algebras, under the new name ``extended affine Lie algebras''. After certain completions, the authors define adjoint groups of extended affine Lie algebras with nullity 2. They show that such groups have Tits systems with affine Weyl groups (Part I). This idea allows to consider linear groups over some completed quantum tori. By the same argument, they prove that these linear groups also have Tits systems with affine Weyl groups. Using this fact they study their universal central extensions as well as associated \(K_1\)-groups and \(K_2\)-groups (Part II). Finally they discuss some relationship among the groups constructed here (Part III).