$\LE$-diagrams and totally positive bases inside the nonnegative Grassmannian

dc.creatorOH, Suho
dc.date2008-09-04
dc.date.accessioned2026-07-07T10:00:43Z
dc.date.available2026-07-07T10:00:43Z
dc.descriptionThere is a cell decomposition of the nonnegative Grassmannian. For each cell, totally positive bases(TP-bases) is defined as the minimal set of Plücker variables such that all other nonzero Plücker variables in the cell can be expressed in those variables in a subtraction-free rational function. This is the generalization of the TP-bases defined for nonnegative part of $GL_k$ defined in \cite{FZ5}. For each cell, we have a $\LE$-diagram and a natural way to label the dots inside the diagram with Plücker variables. Those set of Plücker variables form a TP-bases of the cell. Using mutations coming from 3-term Plücker relation, we conjecture that they can be mutated to a special set of Plücker variable $§$. All other nonzero Plücker variables in the cell will be expressed as a subtraction-free Laurent polynomial in variables of $§$. We define TP-diagrams to express the transformation procedure in terms of moves on a diagram. We will prove the conjecture for certain class of cells called weakly-connected cells. Then we will study the connection with cluster algebras through lattice-path-matroid cells.
dc.description37 pages, 36 figures
dc.identifierhttps://arxiv.org/abs/0809.0871
dc.identifierhttp://arxiv.org/abs/0809.0871
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/168401
dc.subjectCombinatorics
dc.title$\LE$-diagrams and totally positive bases inside the nonnegative Grassmannian
dc.typetext

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