Prossimi seminari del Dipartimento di Matematica

Cristian Gutierrez
A GENERAL HARNACK INEQUALITY FOR SEMILINEAR SUBELLIPTIC EQUATIONS
ore 16:00
presso Aula Vitali
seminario on line • collegamento al meeting (codice: ID riunione: 376 958 557 862 706 Passcode: WM9Uw3tR)
analisi matematica
This series of lectures aims to review the research landscape on high-dimensional dynamical systems, a topic that arises in multiple disciplines. In physics, understanding the many-body dynamics of complex systems is crucial for characterizing their equilibration properties—or the lack thereof. Beyond physics, the study of dynamics is equally vital in optimization and computer science, particularly when dealing with high-dimensional, non-convex problems—such as those encountered in the training dynamics of artificial neural networks. In neuroscience, these systems also model recurrent neural networks, where fixed points, chaos, and control mechanisms shape their behavior. The course has a twofold purpose: first, to survey current knowledge of high-dimensional dynamical systems across various contexts; and second, to explore dynamical mean field theory, the primary toolkit for tackling these challenges. Outline: 1. Stochastic differential equations, Langevin dynamics, Fokker-Planck equation and stationary measures. 2. Equilibrium dynamics and Fluctuation-Dissipation relations. 3. Dynamical mean field theory: Dynamical cavity method 4. Dynamics of mean field spin glasses. High temperature phase and relaxation to equilibrium; Low temperature phase, aging. Landscape interpretation. 5. High-dimensional inference: Langevin/Gradient Descent algorithms and their suboptimality with respect to Approximate Message Passing. 6. Training dynamics of artificial neural networks. Neural tangent kernel and feature learning theory. Separation of timescales between feature learning and overfitting. 7. Recurrent neural networks. Transition to and chaos in high dimension. Maximal Lypaunov exponent. 8. Learning algorithms and optimal control of high-d chaotic dynamics. 9. From Neural ODEs to LLMs and generative models 10. Open problems and perspectives
This series of lectures aims to review the research landscape on high-dimensional dynamical systems, a topic that arises in multiple disciplines. In physics, understanding the many-body dynamics of complex systems is crucial for characterizing their equilibration properties—or the lack thereof. Beyond physics, the study of dynamics is equally vital in optimization and computer science, particularly when dealing with high-dimensional, non-convex problems—such as those encountered in the training dynamics of artificial neural networks. In neuroscience, these systems also model recurrent neural networks, where fixed points, chaos, and control mechanisms shape their behavior. The course has a twofold purpose: first, to survey current knowledge of high-dimensional dynamical systems across various contexts; and second, to explore dynamical mean field theory, the primary toolkit for tackling these challenges. Outline: \\ 1. Stochastic differential equations, Langevin dynamics, Fokker-Planck equation and stationary measures. \\ 2. Equilibrium dynamics and Fluctuation-Dissipation relations. \\ 3. Dynamical mean field theory: Dynamical cavity method \\ 4. Dynamics of mean field spin glasses. High temperature phase and relaxation to equilibrium; Low temperature phase, aging. Landscape interpretation. \\ 5. High-dimensional inference: Langevin/Gradient Descent algorithms and their suboptimality with respect to Approximate Message Passing. \\ 6. Training dynamics of artificial neural networks. Neural tangent kernel and feature learning theory. Separation of timescales between feature learning and overfitting. \\ 7. Recurrent neural networks. Transition to and chaos in high dimension. Maximal Lypaunov exponent. \\ 8. Learning algorithms and optimal control of high-d chaotic dynamics. \\ 9. From Neural ODEs to LLMs and generative models \\ 10. Open problems and perspectives\\
This series of lectures aims to review the research landscape on high-dimensional dynamical systems, a topic that arises in multiple disciplines. In physics, understanding the many-body dynamics of complex systems is crucial for characterizing their equilibration properties—or the lack thereof. Beyond physics, the study of dynamics is equally vital in optimization and computer science, particularly when dealing with high-dimensional, non-convex problems—such as those encountered in the training dynamics of artificial neural networks. In neuroscience, these systems also model recurrent neural networks, where fixed points, chaos, and control mechanisms shape their behavior. The course has a twofold purpose: first, to survey current knowledge of high-dimensional dynamical systems across various contexts; and second, to explore dynamical mean field theory, the primary toolkit for tackling these challenges. Outline: 1. Stochastic differential equations, Langevin dynamics, Fokker-Planck equation and stationary measures. 2. Equilibrium dynamics and Fluctuation-Dissipation relations. 3. Dynamical mean field theory: Dynamical cavity method 4. Dynamics of mean field spin glasses. High temperature phase and relaxation to equilibrium; Low temperature phase, aging. Landscape interpretation. 5. High-dimensional inference: Langevin/Gradient Descent algorithms and their suboptimality with respect to Approximate Message Passing. 6. Training dynamics of artificial neural networks. Neural tangent kernel and feature learning theory. Separation of timescales between feature learning and overfitting. 7. Recurrent neural networks. Transition to and chaos in high dimension. Maximal Lypaunov exponent. 8. Learning algorithms and optimal control of high-d chaotic dynamics. 9. From Neural ODEs to LLMs and generative models 10. Open problems and perspectives
This series of lectures aims to review the research landscape on high-dimensional dynamical systems, a topic that arises in multiple disciplines. In physics, understanding the many-body dynamics of complex systems is crucial for characterizing their equilibration properties—or the lack thereof. Beyond physics, the study of dynamics is equally vital in optimization and computer science, particularly when dealing with high-dimensional, non-convex problems—such as those encountered in the training dynamics of artificial neural networks. In neuroscience, these systems also model recurrent neural networks, where fixed points, chaos, and control mechanisms shape their behavior. The course has a twofold purpose: first, to survey current knowledge of high-dimensional dynamical systems across various contexts; and second, to explore dynamical mean field theory, the primary toolkit for tackling these challenges. Outline: 1. Stochastic differential equations, Langevin dynamics, Fokker-Planck equation and stationary measures. 2. Equilibrium dynamics and Fluctuation-Dissipation relations. 3. Dynamical mean field theory: Dynamical cavity method 4. Dynamics of mean field spin glasses. High temperature phase and relaxation to equilibrium; Low temperature phase, aging. Landscape interpretation. 5. High-dimensional inference: Langevin/Gradient Descent algorithms and their suboptimality with respect to Approximate Message Passing. 6. Training dynamics of artificial neural networks. Neural tangent kernel and feature learning theory. Separation of timescales between feature learning and overfitting. 7. Recurrent neural networks. Transition to and chaos in high dimension. Maximal Lypaunov exponent. 8. Learning algorithms and optimal control of high-d chaotic dynamics. 9. From Neural ODEs to LLMs and generative models 10. Open problems and perspectives
This series of lectures aims to review the research landscape on high-dimensional dynamical systems, a topic that arises in multiple disciplines. In physics, understanding the many-body dynamics of complex systems is crucial for characterizing their equilibration properties—or the lack thereof. Beyond physics, the study of dynamics is equally vital in optimization and computer science, particularly when dealing with high-dimensional, non-convex problems—such as those encountered in the training dynamics of artificial neural networks. In neuroscience, these systems also model recurrent neural networks, where fixed points, chaos, and control mechanisms shape their behavior. The course has a twofold purpose: first, to survey current knowledge of high-dimensional dynamical systems across various contexts; and second, to explore dynamical mean field theory, the primary toolkit for tackling these challenges. Outline: 1. Stochastic differential equations, Langevin dynamics, Fokker-Planck equation and stationary measures. 2. Equilibrium dynamics and Fluctuation-Dissipation relations. 3. Dynamical mean field theory: Dynamical cavity method 4. Dynamics of mean field spin glasses. High temperature phase and relaxation to equilibrium; Low temperature phase, aging. Landscape interpretation. 5. High-dimensional inference: Langevin/Gradient Descent algorithms and their suboptimality with respect to Approximate Message Passing. 6. Training dynamics of artificial neural networks. Neural tangent kernel and feature learning theory. Separation of timescales between feature learning and overfitting. 7. Recurrent neural networks. Transition to and chaos in high dimension. Maximal Lypaunov exponent. 8. Learning algorithms and optimal control of high-d chaotic dynamics. 9. From Neural ODEs to LLMs and generative models 10. Open problems and perspectives
This series of lectures aims to review the research landscape on high-dimensional dynamical systems, a topic that arises in multiple disciplines. In physics, understanding the many-body dynamics of complex systems is crucial for characterizing their equilibration properties—or the lack thereof. Beyond physics, the study of dynamics is equally vital in optimization and computer science, particularly when dealing with high-dimensional, non-convex problems—such as those encountered in the training dynamics of artificial neural networks. In neuroscience, these systems also model recurrent neural networks, where fixed points, chaos, and control mechanisms shape their behavior. The course has a twofold purpose: first, to survey current knowledge of high-dimensional dynamical systems across various contexts; and second, to explore dynamical mean field theory, the primary toolkit for tackling these challenges. Outline: 1. Stochastic differential equations, Langevin dynamics, Fokker-Planck equation and stationary measures. 2. Equilibrium dynamics and Fluctuation-Dissipation relations. 3. Dynamical mean field theory: Dynamical cavity method 4. Dynamics of mean field spin glasses. High temperature phase and relaxation to equilibrium; Low temperature phase, aging. Landscape interpretation. 5. High-dimensional inference: Langevin/Gradient Descent algorithms and their suboptimality with respect to Approximate Message Passing. 6. Training dynamics of artificial neural networks. Neural tangent kernel and feature learning theory. Separation of timescales between feature learning and overfitting. 7. Recurrent neural networks. Transition to and chaos in high dimension. Maximal Lypaunov exponent. 8. Learning algorithms and optimal control of high-d chaotic dynamics. 9. From Neural ODEs to LLMs and generative models 10. Open problems and perspectives
This series of lectures aims to review the research landscape on high-dimensional dynamical systems, a topic that arises in multiple disciplines. In physics, understanding the many-body dynamics of complex systems is crucial for characterizing their equilibration properties—or the lack thereof. Beyond physics, the study of dynamics is equally vital in optimization and computer science, particularly when dealing with high-dimensional, non-convex problems—such as those encountered in the training dynamics of artificial neural networks. In neuroscience, these systems also model recurrent neural networks, where fixed points, chaos, and control mechanisms shape their behavior. The course has a twofold purpose: first, to survey current knowledge of high-dimensional dynamical systems across various contexts; and second, to explore dynamical mean field theory, the primary toolkit for tackling these challenges. Outline: 1. Stochastic differential equations, Langevin dynamics, Fokker-Planck equation and stationary measures. 2. Equilibrium dynamics and Fluctuation-Dissipation relations. 3. Dynamical mean field theory: Dynamical cavity method 4. Dynamics of mean field spin glasses. High temperature phase and relaxation to equilibrium; Low temperature phase, aging. Landscape interpretation. 5. High-dimensional inference: Langevin/Gradient Descent algorithms and their suboptimality with respect to Approximate Message Passing. 6. Training dynamics of artificial neural networks. Neural tangent kernel and feature learning theory. Separation of timescales between feature learning and overfitting. 7. Recurrent neural networks. Transition to and chaos in high dimension. Maximal Lypaunov exponent. 8. Learning algorithms and optimal control of high-d chaotic dynamics. 9. From Neural ODEs to LLMs and generative models 10. Open problems and perspectives
This series of lectures aims to review the research landscape on high-dimensional dynamical systems, a topic that arises in multiple disciplines. In physics, understanding the many-body dynamics of complex systems is crucial for characterizing their equilibration properties—or the lack thereof. Beyond physics, the study of dynamics is equally vital in optimization and computer science, particularly when dealing with high-dimensional, non-convex problems—such as those encountered in the training dynamics of artificial neural networks. In neuroscience, these systems also model recurrent neural networks, where fixed points, chaos, and control mechanisms shape their behavior. The course has a twofold purpose: first, to survey current knowledge of high-dimensional dynamical systems across various contexts; and second, to explore dynamical mean field theory, the primary toolkit for tackling these challenges. Outline: 1. Stochastic differential equations, Langevin dynamics, Fokker-Planck equation and stationary measures. 2. Equilibrium dynamics and Fluctuation-Dissipation relations. 3. Dynamical mean field theory: Dynamical cavity method 4. Dynamics of mean field spin glasses. High temperature phase and relaxation to equilibrium; Low temperature phase, aging. Landscape interpretation. 5. High-dimensional inference: Langevin/Gradient Descent algorithms and their suboptimality with respect to Approximate Message Passing. 6. Training dynamics of artificial neural networks. Neural tangent kernel and feature learning theory. Separation of timescales between feature learning and overfitting. 7. Recurrent neural networks. Transition to and chaos in high dimension. Maximal Lypaunov exponent. 8. Learning algorithms and optimal control of high-d chaotic dynamics. 9. From Neural ODEs to LLMs and generative models 10. Open problems and perspectives
We define, study and implement the model SFV (Symmetrized Fractional Variation): a variational approach to signal analysis exploiting the Riemann-Liouville fractional derivatives of every positive real order higher than zero. The model exploites an L_1 fitting data term together with both right and left fractional derivatives as regularizing terms: this approach aims to achieve an orientation-independent protocol. We express the model as an energy minimization and introduce a functional framework where existence of minimizers is proved: namely the space BVs∗. We show that the embedding in BVs∗ of the Sobolev space of the same fractional order is strict, and we exhibit some nontrivial borderline examples of admissible or non admissible functions in the space BVs∗. To provide evidence of effectiveness for the proposed model, a discretisation based on a second-order consistent Gr¨unwald-Letnikov scheme is introduced. A multi-parameter whiteness criterion is proposed which provides an unsupervised, automatic and simultaneous selection of the two free parameters in the model, namely the fractional order of differentiation and the regularization parameter. Numerical experiments on 1-d and 2-d signals are performed which show how the proposed model holds the potential to achieve good quality results for denoising signals corrupted by additive Laplace noise. This is a joint research with Alessandro Lanza(1), Antonio Leaci(2) and Serena Morigi(1). (1) Dipartimento di Matematica, Universit´a di Bologna (2) Universit´a del Salento, Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Lecce