A quem interessar possa

As datas do curso de Peter Lumsdaine estão confirmadas para:

13 a 17 de Fevereiro
23 e 24 de Fevereiro


Estarei dando umas aulas de introdução ao assunto na semana anterior:

8 a 10 de Fevereiro


As aulas deverão ocorrer no Departamento de Matemática da UFPE, e a sala
ainda está para ser confirmada.

Ruy


---------- Mensagem encaminhada ----------
De: Ruy de Queiroz <r...@cin.ufpe.br>
Data: 24 de novembro de 2011 22:58
Assunto: Curso de Verão (Depto de Matemática): "Homotopy Type Theory", por
Peter Lumsdaine
Para: staff <st...@cin.ufpe.br>, posgrad <posg...@cin.ufpe.br>, grad-l <
gra...@cin.ufpe.br>



Como parte do Programa de Verão
2012<http://www.ufpe.br/verao/index.php?option=com_content&view=article&id=315&Itemid=243>
(Departamento
de Matemática – UFPE, 05 de Janeiro a 24 de Fevereiro de 2012), está
confirmado o mini-curso sobre teoria dos tipos da homotopia, que pode
interessar tanto a matemáticos quanto a cientistas da computação que
trabalham com teoria dos tipos, semântica de linguagens de programação,
provadores automáticos de teorema, e/ou teoria das categorias.

Detalhes sobre inscrição podem ser obtidos por meio de solicitação por
e-mail a verao2012.d...@ufpe.br

Ruy
---

Title: *Homotopy Type Theory*
Instructor: Peter Lumsdaine
<http://mathstat.dal.ca/~p.l.lumsdaine/>(Dalhousie University, Canada)
15 Feb 2012 - 24 Feb 2012

Abstract:

These talks will provide an introduction to Homotopy Type Theory --
the exploration
of a fascinating and fruitful connection between logic and algebraic
topology that has emerged over the last few years.

Dependent Type Theory is a logical system expressive enough to give a
foundation
for mathematics, but at the same time very well-suited to computer
implementation.  In particular, if provides the basic language of many
proof assistants and formalisation systems -- in particular, Coq.

For the most part, its connection to more traditional set-theoretic foundations
is clear and well-understood, and moving between the two does not require
too much change in technique.  An exception to this is its treatment of
equality, which seems considerably more subtle than in classical
foundations (for reasons originally motivated by philosophical and
computational considerations).

The key idea of Homotopy Type Theory is that this strangeness is resolved
if one considers types as corresponding not to classical sets, but to
classical *spaces* (among which sets can still be discerned as the discrete
spaces).  The subtlety of equality can then be understood as coming from
the behavious of *paths* within a space, and be tamed using the insights of
modern algebraic topology.

Practically, this opens up applications in both directions: tools and
intuitions
for working in the type theory on the one hand; and on the other hand, a
very direct approach to the formalisation of algebraic topology.  More
philosophically, it gives a new and beautiful outlook on the universe of
mathematics, with spaces investigated not indirectly as constructed models,
but as fundamental objects of the language, as basic as sets are in the
classical picture.

Besides introducing the general setting, I will discuss Voevodsky's Univalence
Axiom (a strengthening of standard universe axioms), the concept of h-level
(homotopical dimension), and higher inductive types (a technique for
presenting a wide class of spaces, including cell complexes, within the type
 theory).

I'll use the Coq proof assistant for some exercises and examples.  I won't
assume previous familiarity with it, but I recommend getting it and trying
out the interface beforehand.  It's available from http://coq.inria.fr/,
and there are several good introductions online; I recommend the first few
exercises from http://www.cis.upenn.edu/~bcpierce/sf/toc.html.  Warning:
Coq can be
dangerously addictive!  (In the words of Andrew Appel: Coq is the world's
best video game.)

Much more reading (both light and heavy) on Homotopy Type Theory can be
found at http://homotopytypetheory.org.
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