Sala Seminari (Dip. Matematica)

On the scaling limit of Onsager's molecular model for liquid crystals

Relatore: 
Yuning Liu
Abstract. We study the small Deborah number limit of the Doi-Onsager equation for the dynamics of nematic liquid crystals. This is a Smoluchowski-type equation that characterizes the evolution of a number density function, depending upon both particle position and its orientation vector, which lies on the unit sphere.
Data Seminario: 
Wednesday, January 17, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:15
Affiliazione: 
NYU University at Shanghai
Ora Inizio: 
Saturday, January 1, 0000 - 17:15

Singularity formation in critical parabolic equations

Tipo Seminario: 
Relatore: 
Monica Musso

 

Abstract: In this talk I will discuss some recent constructions of blow-up solutions for a Fujita type problem for power $p$ related to the critical Sobolev exponent. Both finite type blow-up (of type II) and infinite time blow-up are considered. This research program is in collaboration with C. Cortazar, M. del Pino and J. Wei.

Data Seminario: 
Wednesday, January 10, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Affiliazione: 
P.U.C. Chile
Ora Inizio: 
Saturday, January 1, 0000 - 17:00

Teoria equivariante dell'intersezione e applicazione in teoria dei moduli

Relatore: 
Andrea Di Lorenzo

Abstract: Il problema di contare il numero di punti in cui si
intersecano due curve in un piano (proiettivo complesso) può avere una
soluzione intuitiva semplice, ma di non facile dimostrazione. La
teoria dei gruppi/anelli di Chow fornisce gli strumenti utili a
rispondere a domande di questo tipo: ad ogni varietà liscia si associa
un anello di Chow, così da trasformare le questioni geometriche di
teoria dell'intersezione in conti algebrici da effettuare in tale
anello.

Data Seminario: 
Wednesday, December 13, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 15:30
Affiliazione: 
Scuola Normale Superiore
Ora Inizio: 
Saturday, January 1, 0000 - 14:00

Renormalized Hennings invariants and TQFTs

Tipo Seminario: 
Relatore: 
Marco De Renzi

Non-semisimple constructions in quantum topology produce strong invariants and TQFTs with unprecedented properties. The first family of non-semisimple quantum invariants of 3-manifolds was defined by Hennings in 1996. The construction enabled Lyubashenko to build mapping class groups representations out of every finite-dimensional factorizable ribbon Hopf algebra. Further attempts at extending these constructions to TQFTs only produced partial results, as the vanishing of Hennings invariants in many crucial situations made it impossible to treat non-connected surfaces.

Data Seminario: 
Wednesday, January 10, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 16:00
Affiliazione: 
Paris Jussieu
Ora Inizio: 
Saturday, January 1, 0000 - 15:00

Volume simpliciale e sue varianti

Relatore: 
Alessandro Divina

Abstract: Il volume simpliciale è un invariante omotopico che misura la complessità dei cicli fondamentali in una varietà, introdotto da M. Gromov nei primi anni ottanta. Nonostante la definizione sia puramente topologica, questo invariante è strettamente legato alla geometria della varietà: per le varietà iperboliche infatti il volume simpliciale è proporzionale al volume Riemanniano.

Data Seminario: 
Wednesday, November 29, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 15:30
Affiliazione: 
Università di Pisa
Ora Inizio: 
Saturday, January 1, 0000 - 14:30

Willmore Flow of Networks

Abstract. We consider networks of curves in the plane moving according to the L^2-gradient flow of a variant of the elastic energy. In this talk we will prove short time existence in the case of networks composed by three curves that are required to meet in one or two triple junctions. As a variation of the result we additionally impose that they form an angle of 120 degrees at the triple junction(s). If time allows we will give some outlook on our expectations concerning the long time behaviour based on numerical work by John Barrett, Harald Garcke and Robert Nürnberg.
Data Seminario: 
Wednesday, November 29, 2017
Relatore: 
Julia Menzel
Ora Fine: 
Saturday, January 1, 0000 - 19:00
Aula: 
Sala Seminari (Dip. Matematica)
Ora Inizio: 
Saturday, January 1, 0000 - 18:00

Minimal Elastic Networks

Abstract. In this talk we will consider planar networks of three curves minimizing a combination of the elastic energy and the length functional. We will prove existence and regularity of minimizers and we will show some properties of the minimal configurations. In addition to the presentation of the results that are obtained in collaboration with Anna Dall'Acqua and Matteo Novaga, we will give a partial review of the theory of elasticae and discuss about the onset of new phenomena passing from the problem for curves to the one for networks.
Data Seminario: 
Wednesday, November 29, 2017
Relatore: 
Alessandra Pluda
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Aula: 
Sala Seminari (Dip. Matematica)
Ora Inizio: 
Saturday, January 1, 0000 - 17:00

Functions of fractal bounded variation

Abstract. In this talk we introduce a notion of functions of fractal bounded variation. Here, the sup-norm of test functions as used in the classical definition is replaced by the Hoelder norm with respect to some exponent. Characteristic functions of domains with fractal bounderies are particular examples that belong to this class. Among a characterization in terms of currents, we state some properties that naturally extend those of classical BV functions such as higher integrability, decomposition into Hoelder functions and push forwards.
Data Seminario: 
Wednesday, November 22, 2017
Relatore: 
Roger Züst
Ora Fine: 
Saturday, January 1, 0000 - 19:00
Aula: 
Sala Seminari (Dip. Matematica)
Ora Inizio: 
Saturday, January 1, 0000 - 18:00

Seminario di Algebra e Teoria dei numeri - Solvable primitive extensions

Relatore: 
Chandan Dalawat

Abstract: A finite separable extension E of a field F is called primitive if there are no intermediate extensions. It is called solvable if the group Gal(Ê |F) of automorphisms of its galoisian closure Ê over F is solvable.  What are the solvable primitive extensions of F ?  This  problem goes back to Évariste Galois; we show how some recent work complements his insights.

Data Seminario: 
Friday, December 1, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 15:30
Affiliazione: 
Harish-Chandra Research Institute
Ora Inizio: 
Saturday, January 1, 0000 - 14:00

Pages

Subscribe to Sala Seminari (Dip. Matematica)