Source: Duke Math. J. Volume 126, Number 1
(2005), 1-52.
We develop a new approach to cluster algebras, based on the notion
of an upper cluster algebra defined as an intersection of Laurent
polynomial rings. Strengthening the Laurent phenomenon established
in [7], we show that under an assumption of
``acyclicity,'' a cluster algebra coincides with its upper
counterpart and is finitely generated; in this case, we also
describe its defining ideal and construct a standard monomial
basis. We prove that the coordinate ring of any double Bruhat cell
in a semisimple complex Lie group is naturally isomorphic to an
upper cluster algebra explicitly defined in terms of relevant
combinatorial data.
Second article in series: S. Fomin, A. Zelevinsky. Cluster Algebras II: Finite Type Classification. Invent. Math. 154 (2003), pp. 63-121.
References
A. Berenstein and A. Zelevinsky, Tensor product multiplicities, canonical bases and totally positive varieties, Invent. Math. 143 (2001), 77--128.
N. Bourbaki, Éléments de mathématique, fasc. 34: Groupes et algèbres de Lie, chapitres 4--6, Actualités Sci. Indust. 1337, Hermann, Paris, 1968.
C. De Concini and C. Procesi, ``Quantum Schubert cells and representations at roots of $1$'' in Algebraic Groups and Lie Groups, Austral. Math. Soc. Lect. Ser. 9, Cambridge Univ. Press, Cambridge, 1997, 127--160.
S. Fomin and A. Zelevinsky, Double Bruhat cells and total positivity, J. Amer. Math. Soc. 12 (1999), 335--380.
--. --. --. --., Recognizing Schubert cells, J. Algebraic Combin. 12 (2000), 37--57.
--. --. --. --., Total positivity: Tests and parametrizations, Math. Intelligencer 22 (2000), 23--33.
--. --. --. --., Cluster algebras I: Foundations, J. Amer. Math. Soc. 15 (2002), 497--529.
--. --. --. --., Cluster algebras II: Finite type classification, Invent. Math. 154 (2003), 63--121.
M. Gekhtman, M. Shapiro, and A. Vainshtein, Cluster algebras and Poisson geometry, Mosc. Math. J. 3 (2003), 899--934.
T. Hoffmann, J. Kellendonk, N. Kutz, and N. Reshetikhin, Factorization dynamics and Coxeter-Toda lattices, Comm. Math. Phys. 212 (2000), 297--321.
M. Kogan and A. Zelevinsky, On symplectic leaves and integrable systems in standard complex semisimple Poisson-Lie groups, Int. Math. Res. Not. 2002, no. 32, 1685--1702.
V. Lakshmibai and C. S. Seshadri, Geometry of $G/P$, V, J. Algebra 100 (1986), 462--557.
B. Leclerc, Imaginary vectors in the dual canonical basis of $U_q(\mathfrakn)$, Transform. Groups 8 (2003), 95--104.
G. Lusztig, ``Total positivity in reductive groups'' in Lie Theory and Geometry: In Honor of Bertram Kostant, Progr. Math. 123, Birkhäuser, Boston, 1994, 531--568.
C. S. Seshadri, ``Geometry of $G/P$, I: Theory of standard monomials for minuscule representations'' in C. P. Ramanujam --.-A Tribute, Tata Inst. Fund. Res. Studies in Math. 8, Springer, Berlin, 1978, 207--239.
B. Shapiro, M. Shapiro, A. Vainshtein, and A. Zelevinsky, Simply laced Coxeter groups and groups generated by symplectic transvections, Michigan Math. J. 48 (2000), 531--551.
A. Zelevinsky, Connected components of real double Bruhat cells, Int. Math. Res. Not. 2000, no. 21, 1131--1153.
--. --. --. --., ``From Littlewood-Richardson coefficients to cluster algebras in three lectures'' in Symmetric Functions 2001: Surveys of Developments and Perspectives, NATO Sci. Ser. II Math. Phys. Chem. 74, Kluwer, Dordrecht, Netherlands, 2002, 253--273.