Kadomtsev--Petviashvili hierarchy is an infinite system of pairwise commuting PDEs. It has a proper description in terms of the Lax operators and commuting flows, but in this course we will work with the KP hierarchy from the point of view of its solutions and will give a description of the formal solutions of the KP hierarchy through the points of the semi infinite Grassmannian. We start with the bosonic and fermionic Fock spaces and the isomorphism between them, then describe a symmetry group which maps one solution to the different one. Then we describe an orbit of this action as an infinite dimensional Grassmannian and rewrite the conditions on tau functions as Hirota bilinear equations. This point of view on KP hierarchy turns out to be very fruitful in applications. We will presents such example as Konstevich--Witten tau function, Orlov--Scherbin tau function and others.
Learning Objectives
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Expected Learning Outcomes
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Course Contents
Fock space
Boson – Fermion correspondence
KP hierarchy
tau functions and algebra gl(∞)
Infinite dimensional Grassmaninans
Hirota bilinear equations
Examples of tau functions from enumerative geometry and enumerative combinatorics
Assessment Elements
HW
Exam
Interim Assessment
2024/2025 2nd module
4 ∗ 0.1 ∗ 𝐻𝑊 + 0.6 ∗ 𝐸, where HW is a grade for the homework (4 during the semester), E is a final exam grade.
Bibliography
Recommended Core Bibliography
Солитоны: дифференциальные уравнения, симметрии и бесконечномерные алгебры, Мива, Т., 2005
Instructors
Bychkov, Boris
Dunin-Barkowski, Petr
Course Syllabus
Abstract
Learning Objectives
Expected Learning Outcomes
Course Contents
Assessment Elements
Interim Assessment
Bibliography
Recommended Core Bibliography
Recommended Additional Bibliography
Authors