Visualization of AE's Training on Credit Card Transactions with Persistent Homology

in Proceedings of the International Workshop on Applications of Topological Data Analysis In conjunction with ECML PKDD 2019 (2019, September)

Auto-encoders are among the most popular neural network architecture for dimension reduction. They are composed of two parts: the encoder which maps the model distribution to a latent manifold and the ... [more ▼]

Auto-encoders are among the most popular neural network architecture for dimension reduction. They are composed of two parts: the encoder which maps the model distribution to a latent manifold and the decoder which maps the latent manifold to a reconstructed distribution. However, auto-encoders are known to provoke chaotically scattered data distribution in the latent manifold resulting in an incomplete reconstructed distribution. Current distance measures fail to detect this problem because they are not able to acknowledge the shape of the data manifolds, i.e. their topological features, and the scale at which the manifolds should be analyzed. We propose Persistent Homology for Wasserstein Auto-Encoders, called PHom-WAE, a new methodology to assess and measure the data distribution of a generative model. PHom-WAE minimizes the Wasserstein distance between the true distribution and the reconstructed distribution and uses persistent homology, the study of the topological features of a space at different spatial resolutions, to compare the nature of the latent manifold and the reconstructed distribution. Our experiments underline the potential of persistent homology for Wasserstein Auto-Encoders in comparison to Variational Auto-Encoders, another type of generative model. The experiments are conducted on a real-world data set particularly challenging for traditional distance measures and auto-encoders. PHom-WAE is the first methodology to propose a topological distance measure, the bottleneck distance, for Wasserstein Auto-Encoders used to compare decoded samples of high quality in the context of credit card transactions. [less ▲]

Quantization of spectral curves and DQ-modules

in Journal of Noncommutative Geometry (2018)

Given an holomorphic Higgs bundle on a compact Riemann surface of genus greater than one, we prove the existence of an holonomic DQ-module supported by the spectral curve associated to this bundle. Then ... [more ▼]

Given an holomorphic Higgs bundle on a compact Riemann surface of genus greater than one, we prove the existence of an holonomic DQ-module supported by the spectral curve associated to this bundle. Then, we relate quantum curves arising in various situations (quantization of spectral curves of Higgs Bundles, quantization of the A-polynomial...) to DQ-modules and show that a quantum curve and the DQ-module canonically associated to it have isomorphic sheaves of solutions. [less ▲]

The codimension-three conjecture for holonomic DQ-modules

in Selecta Mathematica, New Series (2017)

On a complex symplectic manifold, we prove that any holonomic DQ-module endowed with a lattice and defined outside of an analytic subvariety of codimension 3 of its support extends as an holonomic DQ ... [more ▼]

On a complex symplectic manifold, we prove that any holonomic DQ-module endowed with a lattice and defined outside of an analytic subvariety of codimension 3 of its support extends as an holonomic DQ-module. This is an analogue for DQ-modules of the codimension-three conjecture for microdifferential modules recently proved by Kashiwara and Vilonen. [less ▲]

Cohomologically enriched categories and DQ-modules

Presentation (2016, November)

Une brêve introduction aux faisceaux pervers

Presentation (2016, April 13)

Quantization of spectral curves and DQ-modules

Presentation (2016)

Fourier-Mukai transform in the quantized setting

in Advances in Mathematics (2014), 256

We prove that a coherent DQ-kernel induces an equivalence between the derived categories of DQ-modules with coherent cohomology if and only if the graded commutative kernel associated to it induces an ... [more ▼]

We prove that a coherent DQ-kernel induces an equivalence between the derived categories of DQ-modules with coherent cohomology if and only if the graded commutative kernel associated to it induces an equivalence between the derived categories of coherent sheaves. [less ▲]

A Riemann-Roch Theorem for dg Algebras

in Bulletin de la Société Mathématique de France (2013), 141(2), 197-223

Given a smooth proper dg algebra A, a perfect dg A-module M and an endomorphism f of M, we define the Hochschild class of the pair (M,f) with values in the Hochschild homology of the algebra A. Our main ... [more ▼]

Given a smooth proper dg algebra A, a perfect dg A-module M and an endomorphism f of M, we define the Hochschild class of the pair (M,f) with values in the Hochschild homology of the algebra A. Our main result is a Riemann-Roch type formula involving the convolution of two such Hochschild classes. [less ▲]