L'univers des mathématiques

Duration

Dates

Speakers

Description

Honneur à: Pr. Victor Harison

30 to 45 minutes
10/03/2025 from 9 a.m to 10a.m
Victor Harison

Revisiting the stability of a system via the loop analysis method

Duration

Dates

Speakers

Description

Honneur à: Dr. Joseph Rakotondralambo

30 to 45 minutes
10/03/2025 from 10 a.m 45 to 12 a.m
Hosana Valimbavaka Ranaivomanana

On the eigenvalues of Frobenius for a family of Holm elliptic curves

Duration

Dates

Speakers

Substitute

Description:

Let p be a prime number superior or equal to 3, Fp the field with p elements. Let E be the elliptic curve
with equation y^2 = x^3 - x: Let ap be the trace of
the endomorphism of Frobenius on E at p:
For every \lambda belonging in Fp -{0; 1; -1}, we consider the curve H_\lambda with equation  y^3-y =\lambda(x^3- x) associated with E: For the choice of \lambda; H_\lambda is an elliptic curve called a Holm elliptic curve. Let a_p(\lambda) be the trace
of the endomorphism of Frobenius on H_\lambda at p:
We look at the relationship between a_p and the
family { a_p(\lambda)}_{\lambda\neq0,1,-1}:

Honneur à: Aesr. Jacqueline Raveloarisoa

30 to 45 minutes
10/03/2025 from 2 p.m to 3 p.m
François Ramaroson (Online)

Solutions de certaines équations différentielles multiplicativement avancées (MADEs) et leur relation avec les ondelettes et les fonctions spéciales.

Duration

Dates

Speakers

Description:

Nous introduisons des solutions à certaines équations différentielles multiplicativement avancées (MADEs). Puis un ensemble de relations est établi entre leurs transformées de Fourier et les fonctions thêta de Jacobi. Des familles d'ondelettes de solutions aux MADEs et une liste d'applications sont également étudiées.

Honneur à: Dr. Alexis Rafalimanana

30 to 45 minutes
10/03/2025 from 3 p.m 30 to 4 p.m 30
Njinasoa Randriampiry

Tensor Clustering through a Statistical Approach

Duration

Dates

Speakers

Description:

Honneur à: Dr. Armand Ramamonjisoa

30 to 45 minutes
11/03/2025 from  9 a.m to 10 a.m

Dina Faneva Andriantsiory

Ammann Bars for Aperiodic Tilings

Duration

Dates

Speakers

Description

Ammann bars are formed by segments (decorations) on the tiles of a tiling such that forming straight lines with them while tiling forces non-periodicity. Only a few cases are known, starting with Robert Ammann's observations on Penrose tiles, but there is no general explanation or construction. In this article we propose a general method for cut and project tilings based on the notion of subperiods and we illustrate it with an aperiodic set of 36 decorated prototiles related to what we called Cyrenaic tilings.

Honneur à: Dr. Martial Razafimahaleo

30 to 45 minutes
11/03/2025 from 10 a.m 45 to 12 a.m
Carole Porrier

Topics on the theory of non-commutative martingales

Duration

Dates

Speakers

Description
We will give a gentle introduction of noncommutative martingale theory.
Discuss similarities and differences with classical martingales on probability spaces,
some recent results, open problems, and possible future directions.

Honneur à: Dr. Sandrataniaina Andriantsoa

30 to 45 minutes
11/03/2025 from 2 p.m to 3 p.m
Narcisse Randrianantoanina (Online)

Functional Identities on Rings, Applications on Banach algebras and some open problems

Duration

Dates

Speakers

Description:

Let R be a prime ring. Various papers in literature are devoted to classify generalized derivations of R satisfying some functional identities locally on a suitable subset S of R: After recalling some classical results relating to this research area, we will present some new and recent ones. Moreover, using a topological approach based on Baire’s category theorem and some properties of functional analysis, our results have been extended to Banach algebras. We will also propose some open problems on the subject.

Honneur à: Dr. Arsène Ramamonjisoa

30 to 45 minutes
11/03/2025 from  3 p.m 30 to 4 p.m 30
Lahcen Oukhtite

L'indécidabilité : les frontières infranchissables en mathématiques

Duration

Dates

Speakers

Description:

Honneur à: Dr. Olivier Robinson

30 to 45 minutes
12/03/2025 from 9 a.m to 10 a.m
Teodor Knapik

Analyse Harmonique

Duration

Dates

Speakers

Description:

 Honneur à: Dr. Sylvain Ramaromanana

30 to 45 minutes
12/03/2025 from 10 a.m 45 to 12 a.m
Zouhair Mouayn

Des Graphes aux Expanders et Graphons : Exploration via l'Algèbre, l'Algorithmique et les Probabilités

Duration

Dates

Speakers

Description:

 Honneur à: Pr. Arthur Randrianarivony

30 to 45 minutes
12/03/2025 from 2 p.m to 3 p.m
Vlady Ravelomanana

Fifty Years in Mathematics Education

Duration

Dates

Speakers

Description:

La première partie de cette présentation est sur un nouveau résultat au sujet d’une question qui m’a été introduite par un collègue. La seconde partie est sur quelques points de discussions avec un ray aman-dreny de la Science Malagasy – aspects mathématiques de la question de l’énergie, la question fuite de cerveaux, et la malgachisation. Ce qui nous amènera aux deux ‘Grands M’.

Honneur à: Aesr Robert Rabarison

30 to 45 minutes
12/03/2025 from 3 p.m 30 to 4 p.m 30
Kouok Law (Online)

Enseignements des Mathématiques

Duration

Dates

Speakers

Description:

Honneur à: Pr. Michel Martin Rajoelina

30 to 45 minutes
13/03/2025 from 9 a.m to 10 a.m
Fanilo Randriamahaleo

Survey on the Lie Symmetries : Application to the Fractional Partial Differential Equations.

Duration

Dates

Speakers

Description:

The symmetry plays a fundamental role on the laws of nature. In fact the symmetry is everywhere in our life.  The important implication of the symmetry in physics and in mathematics is the existence of conservation laws for any continuous symmetry. These connection between symmetry and conservation laws was establish by Emmy Noether. The study of symmetries of differential equations is an old subject. Thanks to Sophus Lie we today have available to us important information on the behaviour of differential equations. In fact, symmetries can be used to find exact solutions for some nonlinear differential equation. In this talk we give a survey on the Lie symmetry analysis for ordinary and fractional partial  differential equations. The method is illustrated with some  examples.

Honneur à: Aesr. Aimé Rajaonera

30 to 45 minutes
13/03/2025 from 10 a.m 45 to 12 a.m
El Hassan El Kinani (Online)

Paradoxe de sorite

Duration

Dates

Speakers

Description:

Vagues divagations sur le thème du chapitre VIII, “Le sophisme des tas de blé”, du livre “PROBABILITE ET CERTITUDE” de ´ Emile Borel.

Honneur à: Dr Alain Ralambo

30 to 45 minutes
13/03/2025 from  2 p.m to 3 p.m

Narcisse Alain Ralambo

Modelling SARS-CoV-2 evolution on a dynamic immune landscape

Duration

Dates

Speakers

Description:

Since the onset of the pandemic, many SARS-CoV-2 variants have emerged, exhibiting substantial evolution in the virus’ spike protein, the main target of neutralizing antibodies. A plausible hypothesis proposes that the virus evolves to evade antibody-mediated neutralization (vaccine- or infection-induced) to maximize its ability to infect an immunologically experienced population. While virus infection induces neutralizing antibodies, viral evolution may thus navigate on a dynamic immune landscape that is shaped by local infection history. We developed a comprehensive mechanistic model, incorporating deep-mutational scanning data, antibody pharmacokinetics and regional genomic surveillance data to predict the variant-specific relative number of susceptibles over time. We show that this quantity precisely matched historical variant dynamics, predicted future variant dynamics, and explained global differences in variant dynamics. Our work strongly suggests that the ongoing pandemic continues to shape variant-specific population immunity, which determines a variants’ ability to transmit, thus defining variant fitness. The model can be applied to any region by utilizing local genomic surveillance data, allows contextualizing risk assessment of variants, and provides important clues for vaccine design.

Honneur à: Aesr. Emile Andrianjanahary

30 to 45 minutes
13/03/2025 from 3 p.m 30 to 4 p.m 30
Nomenjanahary Alexia Raharinirina (Online)