Campinas
Campinas
São Carlos
São Carlos
Algebra and Geometry meeting
Algebra and Geometry meeting
ICMC, São Carlos, November 6, 2026
This one-day event brings together researchers in Algebra and Geometry from Sao Carlos and Campinas.
There will be invited talks and a poster session.
Gabriel Fazoli
Kaique Matias de Andrade Roberto
Otavio Perez
Vincent Grandjean
Yulia Gorginian
Zhengning Hu
Henrique Sá Earp
Schedule:
conference takes place in Auditorio Fernao Bloco 6, except for morning poster session in Hyperespaco Biblioteca9:45
coffee + poster
Hiperespaco Biblioteca10:30
Vincent Grandjean
Are bifurcation values critical values?11:15
Gabriel Fazoli
Applications of the First Transverse Jet of an Invariant Curve12:00
Henrique Sá Earp
Publishing with AI: dos and donts14:00
Kaique de Andrade Roberto
Generalized Marshall Quotients and Real Semigroups of Continuous and Differentiable Functions14:45
Otavio Perez
Generalized upper principal part of real planar polynomial vector fields15:30
coffee + poster
Auditorio Fernao Bloco 616:15
Yulia Gorginian
TBA17:00
Zhengning Hu
Rational Chow groups of Hurwitz spacesGabriel Fazoli - IMECC - Applications of the First Transverse Jet of an Invariant Curve
In this talk, we study invariant algebraic curves of foliations on algebraic surfaces. An invariant curve carries a natural flat partial connection, whose first transverse jet allows us to study singularities of the curve and of the foliation. Using the associated local indices, we recover the Cerveau–Lins Neto degree bound for smooth invariant curves. We also discuss a rigidity phenomenon: when a scheme naturally associated to this construction has sufficiently small length, the foliation admits an invariant line and, under suitable hypotheses, a rational first integral.Kaique Matias de Andrade Roberto - CLE - Generalized Marshall Quotients and Real Semigroups of Continuous and Differentiable Functions
The theory of real semigroups developed by M. Dickmann and A. Petrovich provides an algebraic framework for abstract real spectra and real algebraic geometry, yet its application to rings of continuous functions is historically hindered by the topological constraints. In this talk, I bridge this gap by introducing generalized Marshall quotients over rings of real-valued continuous and differentiable functions, yielding new explicitly calculated examples of real semigroups. Furthermore, we conclude that the group of invertible elements of these quotients constitutes a real reduced hyperfield (which is categorically equivalent to reduced special groups), addressing the open problem of characterizing when the units of a real semigroup form a reduced special group. Finally, we apply this hyperalgebraic machinery to translate topological and differential phenomena into hyperalgebraic identities, establishing generalized versions of the Lojasiewicz-type inequalities.Otavio Perez - ICMC - Generalized upper principal part of real planar polynomial vector fields
The goal of this paper is to generalize recent results about the topological classification of the dynamics of a real planar polynomial vector field near infinity. Given a polynomial vector field $X$, using Newton polyhedra one can define its generalized upper principal part $X_{\Gamma}^{U}$. By dropping some monomials of $X_{\Gamma}^{U}$, we define its minimal generalized upper principal part $X_{G}^{U}$. We prove that there exist an open and dense set $\widetilde{\mathfrak{U}}_{1}$ in the set of polynomial vector fields with Newton degenerate upper principal part satisfying the following property: if $X\in\widetilde{\mathfrak{U}}_{1}$, then $X$ and $X_{G}^{U}$ are topologically equivalent near infinity, provided that $X_{G}^{U}$ satisfies some additional non-degeneracy assumptions. Our techniques rely on toric compactification and the Normal Form Theorem. Joint work with Thaís Maria Dalbelo and Regilene Oliveira.Vincent Grandjean - UFSC - Are bifurcation values critical values?
I would like to discuss the following problem: a regular map on a non-singular and non-compact variety may admit regular values which are not generic. This is due to a singular behaviour on "the boundary" of its domain. When the mapping is compactified and regularized, what become such values ? It is a joint work with Maria Michalska (ICMC).Yulia Gorginian TBA
Zhengning Hu - IMECC - Rational Chow groups of Hurwitz spaces
The Hurwitz space, parametrizing degree d genus g covers of the projective line up to automorphisms of the target, is a fundamental tool in the study of moduli spaces of curves. In this talk, we shift the focus to the intersection theory on the Hurwitz space itself, and its admissible covers compactification. We will discuss various intersection-theoretic techniques used in computing their rational Chow groups/rings, particularly in the context of double, triple and quadruple covers.morning session 9:45-10:30 hiperespaco biblioteca
Augusto Cezar Abreu Ramos ICMC Quasi-Symmetries of Planar Algebraic CurvesCaio Henrique Silva de Souza ICMC Pseudo-Cauchy sequences and the space of valuationsCristhian Paúl Neyra Salvador UFScar Spectral Sheaves in Meromorphic Higgs Moduli: Boundary Data and DeformationsDiana Hernandes Arriel IMECC Bridgeland stability conditions on the Kuznetsov component of the quintic del Pezzo threefoldDiego Rafael Cotrim Cassemiro IMECC Métodos Geométricos para problemas ElípticosHenrique Tonello Pereira IMECC Teoria de Morse e a Periodicidade de BottIsadora Vanzella Picinini ICMC The integral homology of SL2(Z[1/n])Jesús Eduardo Morales Simons IMECC Analytification of algebraic varieties over non-Archimedean fieldsLeonardo Silva de Oliveira IMECC Moduli space of torsion-free sheaves on P^3Letícia Camponês do Brasil Maia IMECC Generalized Cohomologies of Almost Abelian SolvmanifoldsLuan Carlos Rigoleto Fernandes ICMC On quasi-flat dimension and vanishing of ExtLuiz Otávio de Oliveira Carazolli IMECC Chen-Ruan cohomology of toric orbifoldsMario Ruiz Córdova IMECC Equivalent definitions of periods of algebraic varietiesMilena Brockhof IMECC GIT semistability for pairs of curves with different degreesNelson Prata IMECC Universal vector extension via tannakian formalismNicole Garcia Breves ICMC A study of the real spectrumPaula Cupertino Costa Ribeiro IMECC Classificação de superfícies de Riemann compactas pelo número de automorfismosPaulo Martins ICMC Ischebeck's formula, grade and quasi-homological dimensionsPedro Henrique Amorim Alves ICMC The Schur multiplier of SL_2 and Dedekind zeta functionsPedro Pfarrius Barbassa IMECC Distributions with Unstable Tangent Sheaf on P^3Ricardo Jesús Palomino Piepenborn IME Smooth localizations and C∞-radicals in C∞-ringsRodrigo Santos Monteiro ICMC On Canonical Graph Decompositions via CoveringsVinicius Marcos Manfredini UFScar On topologies on the space of valuations and the valuative treeafternoon session 15:30-16:15 auditorio Fernao bloco 6
Catharina de Moura Moreira ICMC Arithmetic Progressions on Elliptic CurvesJakob Stein IMECC Corrigan-Fairlee- 't Hooft ansatzJoão Marcos Xavier de Lima IMECC Ações de Grupos em Árvores ReaisLeonardo Garcia de Castro IMECC Value Semigroups, Support Semirings and Matroids of a CurveLucas Henrique Martins da Silva IMECC The Generalized Severi Variety: Stratifying the Moduli of Linear Series on $\mathbb P^1$ using Value SemigroupsMauro de Andrade Pinto IMECC Estruturas Complexas Generalizadas em Grupos de Lie Quase AbelianosMiguel Costa Rosales UFScar Uma Introdução à Geometria Algébrica DerivadaNicole Conversano Lavinia IME Towards Lie algebroids over differentiable stacksRenato da Silva Alves de Oliveira ICMC The Geometry of Causality and Time TravelTiago Aprigio ICMC Locally Recoverable Codes on del Pezzo Surfaces of Degree 1