<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-15">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<h1 class="title" id="page-title">The Thurston norm and Fox calculus</h1>
<article class="node-255 node node-seminari node-promoted
view-mode-full clearfix">
<div class="field field-name-field-news-date field-type-date
field-label-hidden">
<div class="field-items">
<div class="field-item even"><span class="date-display-single">Monday,
November 3, 2014</span></div>
</div>
</div>
<div class="field field-name-field-ora-inizio field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Inizio: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">16:00</span></div>
</div>
</div>
<div class="field field-name-field-ora-fine field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Fine: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">17:00</span></div>
</div>
</div>
<div class="field field-name-field-aula
field-type-taxonomy-term-reference field-label-inline clearfix">
<div class="field-label">Aula: </div>
<div class="field-items">
<div class="field-item even"><a
href="http://www.dm.unipi.it/webnew/aula/sala-seminari-dip-matematica">Sala
Seminari (Dip. Matematica)</a></div>
</div>
</div>
<div class="field field-name-field-seminario
field-type-taxonomy-term-reference field-label-hidden">
<div class="field-items">
<div class="field-item even"><a
href="http://www.dm.unipi.it/webnew/seminari/seminari-di-geometria">SEMINARI
DI GEOMETRIA</a></div>
</div>
</div>
<div class="field field-name-field-relatore field-type-text
field-label-inline clearfix">
<div class="field-label">Relatore: </div>
<div class="field-items">
<div class="field-item even">Stephan Friedl</div>
</div>
</div>
<div class="field field-name-field-affiliazione field-type-text
field-label-inline clearfix">
<div class="field-label">Affiliazione: </div>
<div class="field-items">
<div class="field-item even">Regensburg</div>
</div>
</div>
<div class="field field-name-body field-type-text-with-summary
field-label-hidden">
<div class="field-items">
<div class="field-item even">
<p>The Thurston norm of a 3-manifold measures the minimal<br>
complexity of surfaces representing homology classes. We
will show how for some classes of 3-manifolds the Thurston
norm can be determined easily using Fox calculus.<br>
This is joint work with Stephan Tillmann.</p>
</div>
</div>
</div>
</article>
<br>
<h1 class="title" id="page-title">Seminario di divulgazione -
Federico Enriques: Punto di arrivo e punto di partenza.</h1>
<article class="node-248 node node-seminari node-promoted
view-mode-full clearfix">
<div class="field field-name-field-news-date field-type-date
field-label-hidden">
<div class="field-items">
<div class="field-item even"><span class="date-display-single">Tuesday,
November 4, 2014</span></div>
</div>
</div>
<div class="field field-name-field-ora-inizio field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Inizio: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">16:30</span></div>
</div>
</div>
<div class="field field-name-field-ora-fine field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Fine: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">18:30</span></div>
</div>
</div>
<div class="field field-name-field-aula
field-type-taxonomy-term-reference field-label-inline clearfix">
<div class="field-label">Aula: </div>
<div class="field-items">
<div class="field-item even"><a
href="http://www.dm.unipi.it/webnew/aula/aula-magna-dip-matematica">Aula
Magna (Dip. Matematica)</a></div>
</div>
</div>
<div class="field field-name-field-relatore field-type-text
field-label-inline clearfix">
<div class="field-label">Relatore: </div>
<div class="field-items">
<div class="field-item even">Ciro Ciliberto, Università di
Roma "Tor Vergata"</div>
</div>
</div>
<div class="field field-name-field-affiliazione field-type-text
field-label-inline clearfix">
<div class="field-label">Affiliazione: </div>
<div class="field-items">
<div class="field-item even">Seminario organizzato dal Centro
Studi Enriques e l' associazione "La Nuova Limonaia"</div>
</div>
</div>
<div class="field field-name-body field-type-text-with-summary
field-label-hidden">
<div class="field-items">
<div class="field-item even">
<p>In questa conferenza verranno esaminati alcuni dei
contributi di Federigo Enriques<br>
alle varie discipline di cui si e' occupato (matematica,
filosofia, storia delle scienze,<br>
didattica, ecc.) sia come esito di una serie di ricerche
maturate all'interno della<br>
cultura italiana e, piu' in generale, europea nella
seconda meta' del XIX secolo, sia<br>
come punto di partenza per sviluppi successivi fino ai
giorni nostri.</p>
</div>
</div>
</div>
</article>
<br>
<br>
<h1 class="title" id="page-title">Quilting Natural Extensions of
Continued Fraction Expansions</h1>
<article class="node-259 node node-seminari node-promoted
view-mode-full clearfix">
<div class="field field-name-field-news-date field-type-date
field-label-hidden">
<div class="field-items">
<div class="field-item even"><span class="date-display-single">Wednesday,
November 5, 2014</span></div>
</div>
</div>
<div class="field field-name-field-ora-inizio field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Inizio: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">14:30</span></div>
</div>
</div>
<div class="field field-name-field-ora-fine field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Fine: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">15:30</span></div>
</div>
</div>
<div class="field field-name-field-aula
field-type-taxonomy-term-reference field-label-inline clearfix">
<div class="field-label">Aula: </div>
<div class="field-items">
<div class="field-item even"><a
href="http://www.dm.unipi.it/webnew/aula/sala-conferenze-puteano-centro-de-giorgi">Sala
Conferenze (Puteano, Centro De Giorgi)</a></div>
</div>
</div>
<div class="field field-name-field-seminario
field-type-taxonomy-term-reference field-label-hidden">
<div class="field-items">
<div class="field-item even"><a
href="http://www.dm.unipi.it/webnew/seminari/seminari-di-sistemi-dinamici-olomorfi">SEMINARI
DI SISTEMI DINAMICI OLOMORFI</a></div>
</div>
</div>
<div class="field field-name-field-relatore field-type-text
field-label-inline clearfix">
<div class="field-label">Relatore: </div>
<div class="field-items">
<div class="field-item even">Cor Kraaikamp</div>
</div>
</div>
<div class="field field-name-field-affiliazione field-type-text
field-label-inline clearfix">
<div class="field-label">Affiliazione: </div>
<div class="field-items">
<div class="field-item even">TU Delft</div>
</div>
</div>
<div class="field field-name-body field-type-text-with-summary
field-label-hidden">
<div class="field-items">
<div class="field-item even">
<p>Abstract:<br>
In 1981, Hitoshi Nakada introduced a family of continued
fraction maps, and studied<br>
their natural extensions. These are the Nakada
alpha-expansions, which are defined for a<br>
parameter alpha between 0 and 1. These alpha-expansions
played a key role in the revival of<br>
the interest in continued fraction expansions, and are up
to today subject of thorough investigations.<br>
Using some extremely basic ideas called ‘insertions’ and
‘singularizations’ we will show<br>
that there is a strong relation between alpha-expansions
for various values of alpha-expansions.<br>
In this talk I will show how far these ideas can be
carried over, and how they can be used in<br>
other settings, e.g. for the so-called ‘Rosen fractions.’</p>
</div>
</div>
</div>
</article>
<br>
<h1 class="title" id="page-title">On the Dolbeault cohomological
dimension of the moduli space of Riemann surfaces</h1>
<article class="node-253 node node-seminari node-promoted
view-mode-full clearfix">
<div class="field field-name-field-news-date field-type-date
field-label-hidden">
<div class="field-items">
<div class="field-item even"><span class="date-display-single">Tuesday,
November 11, 2014</span></div>
</div>
</div>
<div class="field field-name-field-ora-inizio field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Inizio: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">14:00</span></div>
</div>
</div>
<div class="field field-name-field-ora-fine field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Fine: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">15:00</span></div>
</div>
</div>
<div class="field field-name-field-aula
field-type-taxonomy-term-reference field-label-inline clearfix">
<div class="field-label">Aula: </div>
<div class="field-items">
<div class="field-item even"><a
href="http://www.dm.unipi.it/webnew/aula/sala-seminari-dip-matematica">Sala
Seminari (Dip. Matematica)</a></div>
</div>
</div>
<div class="field field-name-field-seminario
field-type-taxonomy-term-reference field-label-hidden">
<div class="field-items">
<div class="field-item even"><a
href="http://www.dm.unipi.it/webnew/seminari/seminari-di-geometria">SEMINARI
DI GEOMETRIA</a></div>
</div>
</div>
<div class="field field-name-field-relatore field-type-text
field-label-inline clearfix">
<div class="field-label">Relatore: </div>
<div class="field-items">
<div class="field-item even">Gabriele Mondello</div>
</div>
</div>
<div class="field field-name-field-affiliazione field-type-text
field-label-inline clearfix">
<div class="field-label">Affiliazione: </div>
<div class="field-items">
<div class="field-item even">Università di Roma</div>
</div>
</div>
<div class="field field-name-body field-type-text-with-summary
field-label-hidden">
<div class="field-items">
<div class="field-item even">
<p>The moduli space M_g of Riemann surfaces of genus g is
(up to a finite étale cover) a complex manifold and so it
makes sense to speak of its<br>
Dolbeault cohomological dimension (i.e. the highest k such
that<br>
H^{0,k}(M_g,E) does not vanish for some holomorphic vector
bundle E on M_g). The conjecturally optimal bound is g-2,
which is verified for g=2,3,4,5.</p>
<p>In this talk, I will show that such dimension is at most
2g-2.<br>
The key point is to show that the Dolbeault cohomological
dimension of each stratum of the Hodge bundle is at most g
(still non-optimal bound).<br>
In order to do that, I produce an exhaustion function,
whose complex Hessian has controlled index: in the
construction of such a function basic geometric properties
of translation surfaces come into play.</p>
</div>
</div>
</div>
</article>
<br>
<br>
<h1 class="title" id="page-title">Seminario di Geometria - Luoghi
base asintotici per fibrati vettoriali</h1>
<article class="node-249 node node-seminari node-promoted
view-mode-full clearfix">
<div class="field field-name-field-news-date field-type-date
field-label-hidden">
<div class="field-items">
<div class="field-item even"><span class="date-display-single">Wednesday,
November 12, 2014</span></div>
</div>
</div>
<div class="field field-name-field-ora-inizio field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Inizio: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">15:00</span></div>
</div>
</div>
<div class="field field-name-field-ora-fine field-type-datetime
field-label-inline clearfix">
<div class="field-label">Ora Fine: </div>
<div class="field-items">
<div class="field-item even"><span class="date-display-single">16:00</span></div>
</div>
</div>
<div class="field field-name-field-aula
field-type-taxonomy-term-reference field-label-inline clearfix">
<div class="field-label">Aula: </div>
<div class="field-items">
<div class="field-item even"><a
href="http://www.dm.unipi.it/webnew/aula/sala-riunioni-dip-matematica">Sala
Riunioni (Dip. Matematica)</a></div>
</div>
</div>
<div class="field field-name-field-relatore field-type-text
field-label-inline clearfix">
<div class="field-label">Relatore: </div>
<div class="field-items">
<div class="field-item even">Ernesto Mistretta, Università di
Padova</div>
</div>
</div>
<div class="field field-name-body field-type-text-with-summary
field-label-hidden">
<div class="field-items">
<div class="field-item even">
<p>Richiamiamo la costruzione dei luoghi base asintotici<br>
(luogo base stabile, luogo base aumentato e luogo base
ristretto)<br>
per fibrati in rette,<br>
e definiamo in maniera analoga dei luoghi base asintotici
per fibrati<br>
vettoriali,<br>
collegandoli ad alcune proprieta' di positivita' esistenti
nella letteratura<br>
(positivita' debole di Viehweg, ampiezza quasi ovunque,
altre condizioni).<br>
Mostriamo una costruzione alla Iitaka per le mappe di
valutazione per<br>
fibrati vettoriali.<br>
Si tratta di un lavoro in corso, effettuato in parte in
collaborazione<br>
con S. Urbinati, in parte con<br>
T. Bauer, S. Kovács, A. Küronya, e T. Szemberg.</p>
</div>
</div>
</div>
</article>
<br>
<br>
<br>
<br>
<br>
<pre class="moz-signature" cols="72">--
Carla Spinelli
Dipartimento di Matematica
via F.Buonarroti, 1
ex-DMA - piano terra
Università di Pisa
tel.050-2213825 e.mail - spinelli(at)dm.unipi.it </pre>
</body>
</html>