Matrix-valued measures and integration on foundation semigroups

Document Type : Original Article

Author

Kyrgyz-Turkish Manas University, Bishkek, Kyrgyzstan

Abstract

This paper develops a comprehensive theory of matrix-valued measures and integration on foundation topological semigroups, extending the well-established framework for topological groups. We establish fundamental results, including polar decomposition, duality theory, and convolution algebras for $M_n$-valued measures. The paper characterizes several important classes of measures ($\Mel$, $\Mer$, $\Mal$, $\Mar$) and analyzes their structural properties, showing that $\Ma$ forms an L-ideal and $\Me$ is an L-subalgebra. Finally, we develop a theory of quasi-invariant matrix-valued measures, proving existence results and characterizing the measure algebra $\Me$ in terms of equi-quasi-invariant measures. Our work provides a unified framework for non-commutative harmonic analysis on semigroups, generalizing both the scalar theory for foundation semigroups and the matrix-valued theory for groups.

Keywords

Main Subjects


[1] Baker, A.C., & Baker, J.W. (1969). Algebras of measures on a locally compact semigroup. J. London Math. Soc, 1(2), 249–259. DOI: https://doi.org/10.1112/jlms/s2-1.1.249.
[2] Baker, A.C., & Baker, J.W. (1970). Algebras of measures on a locally compact semigroup II.
J. London Math. Soc, 2, 651–659. DOI: https://doi.org/10.1112/jlms/2.Part_4.651.
[3] Baker, A.C., & Baker, J.W. (1972). Algebras of measures on a locally compact semigroup III.
J. London Math. Soc, 4(2), 685–695. DOI: https://doi.org/10.1112/jlms/s2-4.4.685.
[4] Chu, C-H. (2002). Matrix-valued harmonic functions on groups.
J. reine angew. Math, 552, 15–52. https://doi.org/10.1515/crll.2002.089.
[5] Chu, C-H. (2008). Matrix Convolution Operators on Groups.
Lecture Notes in Mathematics, Springer-Verlag Berlin Heidelberg. DOI: https://doi.org/10.1007/978-3-540-69798-5_3.
[6] Chu, C-H., & Lau, A. T-M. (2006). Jordan structures in harmonic functions and Fourier algebras on homogeneous spaces.
Math. Ann, 336, 803–840. https://doi.org/10.1007/s00208-006-0013-y.
[7] Dzinotyiweyi, H.A.M. (1978). On the analogue of the group algebra for locally compact semigroups.
J. London Math. Soc, 2(3), 489–506. DOI: https://doi.org/10.1112/jlms/s2-17.3.489.
[8] Ebadian, A., & Jabbari, A. (2020). Matrix valued p-convolution operators. Oper. Matrices, 14(1), 117–128. DOI: http://dx.doi.org/10.7153/oam-2020-14-09. 
[9] Ebadian, A., & Jabbari, A. (2021). Matrix valued conjugate convolution operators on matrix valued Lp-spaces. Math. Inequal. Appl, 24(3), 827–844. http://dx.doi.org/10.7153/mia-2021-24-57.
[10] Ebadian, A., & Jabbari, A. (2023). Representations and Bochner’s theorem for matrix valued group algebras.
J. Math. Anal. Appl, 528(1), 127542. https://doi.org/10.1016/j.jmaa.2023.127542.
[11] Grothendieck, A. (1953). Sur les applications lineaires faiblement compactes d’espaces du type C(K).
Canad. J. Math, 5, 129–173. https://doi.org/10.4153/CJM-1953-017-4.
[12] Jabbari, A. (2020). Positive type and positive definite functions on matrix valued group algebras.
Results Math, 75(4), Art. N. 149 (25 pages). https://doi.org/10.1007/s00025-020-01278-1.
[13] Lashkarizadeh Bami, M. (1985). Representations of foundation semigroups and their algebras.
Canad. J. Math, 37(1), 29–47. https://doi.org/10.4153/CJM-1985-003-0.