Abstract
We discuss the solvability of two Cauchy problems in matrix pseudodifferential operators. The first is associated with a set of matrix pseudodifferential operators of negative order, a prominent example being the set of strict integral operator parts of products of a solution \((L,\{U_\alpha\})\) of the \(\mathbf h[\partial]\)-hierarchy, where \(\mathbf h\) is a maximal commutative subalgebra of \(gl_n(\mathbb{C})\). We show that it can be solved in the case of compatibility completeness of the adopted setting. The second Cauchy problem is slightly more general and relates to a set of matrix pseudodifferential operators of order zero or less. The key example here is the collection of integral operator parts of the different products of a solution \(\{V_\alpha\}\) of the strict \(\mathbf h[\partial]\)-hierarchy. This system is solvable if two properties hold: the Cauchy solvability in dimension \(n\) and the compatibility completeness. Both conditions are shown to hold in the formal power series setting.
Similar content being viewed by others
References
G. F. Helminck, “Integrable deformations in the matrix pseudo differential operators,” J. Geom. Phys., 113, 104–116 (2017).
G. Wilson, “Commuting flows and conservation laws for Lax equations,” Math. Proc. Cambridge Philos. Soc., 86, 131–143 (1979).
E. Date, M. Jimbo, M. Kashiwara, and T. Miwa, “Operator approach to the Kadomtsev–Petviashvili equation. Transformation Groups for Soliton Equations III,” J. Phys. Soc. Japan, 50, 3806–3812 (1981).
G. F. Helminck and G. F. Post, “A convergent framework for the multicomponent KP-hierarchy,” Trans. Amer. Math. Soc., 324, 271–292 (1991).
M. Gerstenhaber, “On dominance and varieties of commuting matrices,” Ann. Math., 73, 324–348 (1961).
R. C. Courter, “The dimension of maximal commutative subalgebras of \(K_n\),” Duke Math. J., 32, 225–232 (1965).
T. J. Laffey, “The minimal dimension of maximal commutative subalgebras of full matrix algebras,” Linear Algebra Appl., 71, 199–212 (1985).
I. Schur, “Zur Theorie der vertauschbaren Matrizen,” J. Reine Angew. Math., 130, 66–76 (1905).
N. Jacobson, “Schur’s theorems on commutative matrices,” Bull. Amer. Math. Soc., 50, 431–436 (1944).
M. Mirzakhani, “A simple proof of a theorem of Schur,” Amer. Math. Monthly, 105, 260–262 (1998).
G. F. Helminck and J. W. van de Leur, “Darboux transformations for the KP-hierarchy in the Segal–Wilson setting,” Canad. J. Math., 53, 278–309 (2001).
G. F. Helminck, V. A. Poberezhny, and S. V. Polenkova, “Strict versions of integrable hierarchies in pseudodifference operators and the related Cauchy problems,” Theoret. and Math. Phys., 198, 197–214 (2019).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
The author declares no conflicts of interest.
Additional information
Prepared from an English manuscript submitted by the author; for the Russian version, see Teoreticheskaya i Matematicheskaya Fizika, 2023, Vol. 216, pp. 251–270 https://doi.org/10.4213/tmf10378.
Rights and permissions
About this article
Cite this article
Helminck, G.F. Cauchy problems related to integrable matrix hierarchies. Theor Math Phys 216, 1124–1141 (2023). https://doi.org/10.1134/S0040577923080056
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0040577923080056