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Walter A. Burkhard
Professor and Chairman
Department of Computer Science and Engineering
Mail Code C-014
University of California, San Diego
LaJolla, California  92093-0114
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Dear Professor Burkhard:

	I haven't followed Robert Filman's research since the he got
his PhD, because our interests have diverged.  As for his thesis, he
did a very creditable job on what turned out to be an excessively hard
and tedious problem.  I'm not surprised that he didn't continue along
that line.

	The problem was to study the epistemology of combined observation
and logical reasoning.  The domain I suggested to him was based on a
retrospective analysis chess problem --- determining what piece had fallen
of the board from a given square given the rest of the position.  Filman's
job was to make an interactive theorem prover accept the reasoning
justifying the rather clever solution.  I believe it is still the largest
piece of nonmathematical reasoning to be verified by computer program,
and Filman had to introduce several new concepts in order to do the job.
Unfortunately, the problem was too intricate for the results to be
readily expoundable, and the thesis got too long.

	My sources tell me that Filman was a successful teacher at the
University of Indiana.

	Sorry not to have more comments on his recent work.

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Sincerely,
John McCarthy
Professor
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