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Master's Thesis
Author of thesis: Foster Agyei
Acad. year: 2025/2026
Supervisor: doc. Mgr. et Mgr. Aleš Návrat, Ph.D.
Reviewer: doc. Mgr. Petr Vašík, Ph.D.
This thesis explores the basic mathematical relationship between deep learning architectures' expressivity and geometric control theory. Using Deep Residual Neural Networks (ResNets) as continuous-time dynamical systems controlled by Neural Ordinary Differential Equations (Neural ODEs), we show that the algebraic properties of the underlying vector fields and the Lie Algebra Rank Condition (LARC) determine a network's ability to approximate complex coordinate transformations. By reinterpreting individual network layers as discrete snapshots of a continuous velocity flow, this continuous lens changes the training objective from learning static, disconnected weights to identifying a smooth, time-dependent control function. Formulating and analyzing this training process as a regularized continuous-time optimal control problem is the main goal of this work. Using co-state trajectories and a step-size backtracking line-search mechanism, we implement an iterative framework based on the discrete Pontryagin Maximum Principle (PMP) to efficiently optimize this structure without depending on conventional discrete backpropagation. Using this configuration, we study the effects of extreme spatial curvature and boundary deformations on various geometric designs of controlled vector fields. In order to guarantee smooth, stable continuous flows that preserve valid coordinate diffeomorphisms without producing spatial ripping or overfitting, we finally investigate the critical role of an L^2 control regularization penalty in limiting high-energy control operations.
Control-Linear Systems, Neural ODEs, Residual Neural Networks (ResNets), Geometric Control Theory, Ensemble Controllability, Lie Brackets, Chow-Rashevskii Theorem, Pontryagin Maximum Principle (PMP), Universal Approximation, Diffeomorphisms.
Date of defence
17.06.2026
Result of the defence
Defended (thesis was successfully defended)
Grading
E
Process of defence
Student presented his Master's thesis. Then hy presented Algorithm 1 from the thesis to answer reviewer comment about the level he understand the work (and suggestion that the thesis was heavily generated by AI). Then he answered questions of prof. Protasov regarding particular expressions in thesis's presentation.
Language of thesis
English
Faculty
Fakulta strojního inženýrství
Department
Institute of Mathematics
Study programme
Applied and Interdisciplinary Mathematics (N-AIM-A)
Composition of Committee
prof. RNDr. Josef Šlapal, CSc. (předseda) doc. Ing. Luděk Nechvátal, Ph.D. (místopředseda) doc. Ing. Petr Tomášek, Ph.D. (člen) prof. Mgr. Pavel Řehák, Ph.D. (člen) doc. Ing. Tomáš Kisela, Ph.D. (člen) Prof. Vladimir Protasov (člen)
Supervisor’s reportdoc. Mgr. et Mgr. Aleš Návrat, Ph.D.
Grade proposed by supervisor: D
Reviewer’s reportdoc. Mgr. Petr Vašík, Ph.D.
Grade proposed by reviewer: E
Responsibility: Mgr. et Mgr. Hana Odstrčilová