Abstract
We give combinatorial formulas for the Laurent expansion of any cluster variable in any cluster algebra coming from a triangulated surface (with or without punctures), with respect to an arbitrary seed. Moreover, we work in the generality of principal coefficients. An immediate corollary of our formulas is a proof of the positivity conjecture of Fomin and Zelevinsky for cluster algebras from surfaces, in geometric type.
Original language | English (US) |
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Pages (from-to) | 2241-2308 |
Number of pages | 68 |
Journal | Advances in Mathematics |
Volume | 227 |
Issue number | 6 |
DOIs | |
State | Published - Aug 20 2011 |
Bibliographical note
Funding Information:✩ The first author is supported by the NSF research grant DMS-1067183; the second author is supported by the NSF research grants DMS-0908765 and DMS-1001637, and by the University of Connecticut; and the third author is supported by the NSF research grant DMS-0854432 and an Alfred Sloan Research Fellowship. * Corresponding author. E-mail addresses: [email protected] (G. Musiker), [email protected] (R. Schiffler), [email protected] (L. Williams).
Keywords
- Cluster algebra
- Positivity conjecture
- Triangulated surfaces