Computability and complexity theory are two central areas
of research in mathematical logic and theoretical computer
science. Computability theory is the study of the limitations
and abilities of computers in principle. Computational
complexity theory provides a framework for understanding the
cost of solving computational problems, as measured by the
requirement for resources such as time and space.
The classical approach in these areas is to consider
algorithms as operating on finite strings of symbols from a
finite alphabet. Such strings may represent various discrete
objects such as integers or algebraic expressions, but cannot
represent general real or complex numbers, unless they are
rounded.

Most mathematical models in physics and engineering, however,
are based on the real number concept. Thus, a computability
theory and a complexity theory over the real numbers and over
more general continuous data structures is needed. Despite
remarkable progress in recent years many important fundamental
problems have not yet been studied, and presumably numerous
unexpected and surprising results are waiting to be detected.

Scientists working in the area of computation on real-valued
data come from different fields, such as theoretical computer
science, domain theory, logic, constructive mathematics,
computer arithmetic, numerical mathematics and all branches
of analysis. The conference provides a unique opportunity for
people from such diverse areas to meet, present work in progress
and exchange ideas and knowledge.

The topics of interest include foundational work on various
models and approaches for describing computability and
complexity over the real numbers. They also include
complexity-theoretic investigations, both foundational and
with respect to concrete problems, and new implementations of
exact real arithmetic, as well as further developments of
already existing software packages. We hope to gain new
insights into computability-theoretic aspects of various
computational questions from physics and from other fields
involving computations over the real numbers.

- Computable analysis
- Complexity on real numbers
- Constructive analysis
- Domain theory and analysis
- Theory of representations
- Computable numbers, subsets and functions
- Randomness and computable measure theory
- Models of computability on real numbers
- Realizability theory and analysis
- Real number algorithms
- Implementation of exact real number arithmetic

**Mark Braverman**(Cambridge, USA)**Vladik Kreinovich**(El Paso, USA)**Dana Scott**(Pittsburgh, USA)**Ning Zhong**(Cincinnati, USA)

**Martín Escardó**(Birmingham, UK)**Bas Spitters**and**Russell O'Connor**(Eindhoven, The Netherlands)

**Andrej Bauer**(Ljubljana, Slovenia)**Vasco Brattka**(Cape Town, South Africa)**Mark Braverman**(Cambridge, USA)**Pieter Collins**(Amsterdam, The Netherlands)**Peter Hertling**, co-chair (Munich, Germany)**Hajime Ishihara**(Ishikawa, Japan)**Ker-I Ko**, co-chair (Stony Brook, USA)**Robert Rettinger**(Hagen, Germany)**Victor Selivanov**(Novosibirsk, Russia)**Alex Simpson**(Edinburgh, Great Britain)**Dieter Spreen**(Siegen, Germany)**Frank Stephan**(Singapore)**Xizhong Zheng**(Glenside, USA)

**Andrej Bauer**, chair**Iztok Kavkler****Davorin Lešnik****Matija Pretnar**

University of Ljubljana and

Institute of Mathematics, Physics and Mechanics.

http://www.easychair.org/conferences/?conf=cca2009

These extended abstracts should be prepared using
the LNCS stylefile of Springer Verlag; see

http://www.springer.com/computer/lncs?SGWID=0-164-7-72376-0

**Ker-I Ko**, PC co-chair (for submissions)**Peter Hertling**, PC co-chair (for submissions)**Andrej Bauer**, local organizer (for local information)