Matemática

João Martins

O que fazem e o que pensam alguns membros da comunidade de Ciências? O Dictum et factum de fevereiro de 2018 é com João Martins, técnico superior do Departamento de Física de Ciências.

Robinson-Schensted and RSK correspondences for Skew and Skew Shifted Tableaux

Por Inês Martins Rodrigues (aluna de doutoramento da FCUL).

Abstract: The Robinson-Schensted correspondence, introduced by Schensted (1961) in its most well-known form, presents a bijective correspondence between permutations and pairs of standard Young tableaux of the same shape. Knuth (1970) presented a generalization, the RSK correspondence, for semistandard Young tableaux.

Using o-minimality to compute lower bounds on sample complexity of neural networks

Por Alex Usvyatsov (Universidade de Lisboa, CMAF-CIO).

Abstract: I will discuss the concept of sample complexity in statistical learning theory. Then I will show how definability of many hypothesis classes (for example, essentially all artificial neural networks used in practice) in o-minimal structures, helps to compute tighter lower bounds on sample complexity for these hypothesis classes.

Nonlinear Dirichlet Problems: Old and New

Por Lucio Boccardo (Dipartimento di Matematica, "Sapienza" Università di Roma).

Abstract: We present a review on the Stampacchia-Calderon-Zygmund theory for linear elliptic operators of second order with discontinuous coefficients and the corresponding theory for nonlinear operators of Leray-Lions type with nonregular data.

We shall also discuss classical and recent results, including work in progress, on the continuous dependence of the solutions with respect to right hand sides.

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