TY - JOUR

T1 - Closed Mappings and Construction of Extension Models

AU - Chentsov, A.

N1 - This work was supported by ongoing institutional funding. No additional grants to carry out or direct this particular research were obtained.

PY - 2023/12/1

Y1 - 2023/12/1

N2 - The problem of reachability in a topological space is studied under constraints of asymptotic nature arising from weakening the requirement that the image of a solution belong to a given set. The attraction set that arises in this case in the topological space is a regularization of certain kind for the image of the preimage of the mentioned set (the image and the preimage are defined for generally different mappings). When constructing natural compact extensions of the reachability problem with constraints of asymptotic nature generated by a family of neighborhoods of a fixed set, the case was studied earlier where the topological space in which the results of one or another choice of solution are realized satisfies the axiom T2. In the present paper, for a number of statements related to compact extensions, it is possible to use for this purpose a T1 space, which seems to be quite important from a theoretical point of view, since it is possible to find out the exact role of the axiom T2 in questions related to correct extensions of reachability problems. We study extension models using ultrafilters of a broadly understood measurable space with detailing of the main elements in the case of a reachability problem in the space of functionals with the topology of a Tychonoff power of the real line with the usual -topology. The general constructions of extension models are illustrated by an example of a nonlinear control problem with state constraints.

AB - The problem of reachability in a topological space is studied under constraints of asymptotic nature arising from weakening the requirement that the image of a solution belong to a given set. The attraction set that arises in this case in the topological space is a regularization of certain kind for the image of the preimage of the mentioned set (the image and the preimage are defined for generally different mappings). When constructing natural compact extensions of the reachability problem with constraints of asymptotic nature generated by a family of neighborhoods of a fixed set, the case was studied earlier where the topological space in which the results of one or another choice of solution are realized satisfies the axiom T2. In the present paper, for a number of statements related to compact extensions, it is possible to use for this purpose a T1 space, which seems to be quite important from a theoretical point of view, since it is possible to find out the exact role of the axiom T2 in questions related to correct extensions of reachability problems. We study extension models using ultrafilters of a broadly understood measurable space with detailing of the main elements in the case of a reachability problem in the space of functionals with the topology of a Tychonoff power of the real line with the usual -topology. The general constructions of extension models are illustrated by an example of a nonlinear control problem with state constraints.

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U2 - 10.1134/S0081543823060056

DO - 10.1134/S0081543823060056

M3 - Article

VL - 323

SP - S56-S77

JO - Proceedings of the Steklov Institute of Mathematics

JF - Proceedings of the Steklov Institute of Mathematics

SN - 0081-5438

IS - S1

ER -