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JOURNALS // Vladikavkazskii Matematicheskii Zhurnal // Archive

Vladikavkaz. Mat. Zh., 2024 Volume 26, Number 4, Pages 21–27 (Mi vmj927)

Inversion of Radon transformation for discontinuous functions in unbounded sets

D. S. Anikonov, D. S. Konovalova

Sobolev Institute of Mathematics of the Siberian Branch of the RAS, 4 Ac. Koptyug Ave., Novosibirsk 630090, Russia

Abstract: This work relates to the theory of integral geometry in Euclidean space. The object to be searched is an information about the integrand for some given set of integrals. Similar settings are in demand in the theory of differential equations. Such investigations have been presented, for example, in the works of D. Radon, R. Courant, F. Jon, I. M. Gelfand. Later the use of integral geometry was associated with the study of inverse problems for differential equations. In particular, some formulations of inverse problems coincided with the problems of integral geometry. This circumstance has been widely used in works of the mathematical school of M. M. Lavrentiev and V. G. Romanov. From related areas of research, we note first of all probing environment with physical signals. Probably currently the most well-known area is $X$-ray tomography for needs of medicine and technology. More specifically, we mean theory of classical and generalized Radon transformations. In this area numerous results are received for Radon transformations. Moreover, some of the uniqueness theorems have been proven for fairly weak constraints. But the inversion formulas have been proven only for smooth functions. This circumstance somewhat reduces their applied value. This prompted the authors of this work to study specifically the cases of discontinuous integrands. An essential element of the proposed research is to introduce the concept of pseudoconvex sets on which unknown discontinuous functions are defined. Such sets turned out to be, on the one hand, not burdensome for the theory of probing, and on the other hand, convenient for research. So far it has been possible to study only the case of odd-dimensional Euclidean space.

Key words: Radon transform, pseudoconvex sets, integral geometry, probing, tomography, discontinuous functions, inversion formula.

UDC: 517.44

MSC: 44A12

Received: 05.01.2024

DOI: 10.46698/e9041-1168-6207-j



© Steklov Math. Inst. of RAS, 2025