Four speakers are chosen for the NVTI Theory Day along two axis: In
and out of the Netherlands, and Theory A and Theory B. For example I was the
non-Dutch Theory A speaker. But what is Theory A and B?
In 1994, the Handbook
of Theoretical Computer Science was published as a two volume
set each containing many survey articles that have for the most part
stood the test of time. From the backcover: Volume A [Algorithms and
Complexity] covers models of computation, complexity theory, data
structure and efficient computation. Volume B [Formal Models and
Semantics] presents material on automata and rewriting systems,
foundations of programming languages, logics for program specification
and verification and modeling of advanced information processing.
Over the years, Theory A and Theory B have come to represent the areas
discussed in the corresponding volumes. In the US the term theoretical
computer science covers areas mostly in Theory A. For example STOC and
FOCS, the major US theory conferences, cover very little in Theory
B. This is not to say Theory B is not done in this country; it is just
labelled as logic or programming languages.
Outside the US there is a broader view of what is theory. The European
ICALP conference covers
both areas and has two submission tracks A and B that again correspond to
Theory A and B.
Some countries, like Britain and France, focuses mostly on Theory
B. Other countries, like the Netherlands and Germany have many groups
in both areas.
Some Europeans are upset that their research is not considered theory
by the Americans. Too bad.