My primary research theme is the mathematics of computation (how to describe the act of performing computations by man, alien, or machine by mathematics). This includes computing and calculations involving mathematical structures that are intrinsically infinite in nature, but must necessarily be computed using only finite resources.
    In addition, I maintain a serious professional interest in other areas of computer science such as information retrieval and human-computer interaction.
    Currently, I work in the following areas:
    Computability Theory
    Rewriting and Lambda Calculus
    Complexity Theory
    Information Retrieval
    Symbolic Dynamical Systems
    I have previously been active in the following areas:
    Constructive/Computable/Recursive Mathematics
    Human-computer Interaction