I am interested in all aspects of computational complexity, including machine-based complexity, communication complexity, models of parallel computation, distributed computation, algorithms, as well as problems inspired by the world wide web.
I am working on complexity theory, and algorithms in diverse subareas: combinatorial algorithms, algorithms in bioinformatics, algorithms for distributed systems, etc.
I am interested in learning about techniques that may provide tools for proving lower bounds.
More or less recent work on combinatorial algorithms includes graph theoretic models of optical networks, in particular the complexity of assigning wavelengths to optical communication paths, and graph problems inspired by the model.
Recent work on distributed algorithms includes algorithms for information distribution in (very idealized) mobile networks. I have a nagging interest in the firing squad problem for cellular automata. I am also interested in error tolerance.
There are interesting combinatorial problems whose solution is of interest to biologists.
I have interests in electronic publishing, and in the uses of the Internet--both the technical problems and the social implications.
I will try to keep this up to date.
A scanned version of our out-of-print book Aspectos Teóricos da Computação, (with Cláudio L. Lucchesi, Imre Simon, Istvan Simon, and Tomasz Kowaltowski) can be accessed from its USP mirror.