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C00002 00002	.require "let.pub" source
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.require "let.pub" source
.macro ltr(add,sal) ⊂
∂AIL add ∞

Dear sal:

	Robert Filman has just completed his PhD dissertation under my
direction, and it is in the hands of the readers.  He has just passed his
final oral examination, and I expect him to complete all work for his
PhD in Winter Quarter or Spring Quarter at the latest.

	His thesis opens a new part of the epistemology of artificial
intelligence - studying reasoning that combines inference and observation.
To my knowledge this is the first research paper in the area.

	Its importance comes from the fact that much human reasoning
does not follow the model of pure mathematics but combines facts coming
from observation of the world with general premises - here expressed
as axioms.  The problem chosen was in retrospective chess analysis -
determining what piece fell off the board in a chess position, given
that the position arose in a legal game of chess.  The reasoning
involved differs in many subtle ways from that involved in the proof
of a mathematical theorem.

	Filman has done an excellent job of formalizing this reasoning to
the extent that the proof can be generated and checked using FOL, our
first order logic interactive theorem prover and proof checker.  In the
course of this, he has made many improvements to FOL, necessitated by the
fact that this was the largest task undertaken with FOL and used many
previously untested features.  He has exhibited a high degree of
originality in deciding how to translate vague informal concepts into a
precise mathematical formalism.  The work also required great
perseverance, and Filman has shown it in completing his thesis less than
three years of graduate work at Stanford.
.next page
	Filman has given numerous presentations of his work and
served as a teaching assistant.  His oral presentation is also
excellent, and I expect him to be an excellent teacher.  He
also has a co-operative and pleasant personality.

.sgn
. ⊃

.ltr(|Professor Paul Young↓Department of Computing and Information Science
.↓The University of New Nexico↓Albuquerque, New Mexico 87131|,Professor Young);

.if false then begin
.ltr(|Professor Jonathan L. Gross↓Department of Mathematical Statistics
.↓618 Mathematics↓Columbia University↓New York, New York 10027|,Professor Gross);

.ltr(|Prof. Paul W. Purdom, Jr.↓Chairman, Computer Science Department↓Lindley Hall 101
.↓Indiana University↓Bloomington, Indiana 47401|,Professor Purdom);

.ltr(|Prof. David Young, Jr.↓Chairman, Recruiting Committee↓Department of Computer Science
.↓University of Texas↓Austin, Texas 78712|,Professor Young);

.ltr(|Professor Michael A. Arbib↓Chairman of the Personnel Committee
.↓Department of Computer and Information Science↓Graduate Research Center
.↓University of Massachusetts↓Amherst Massachusetts 01003|,Professor Arbib);

.ltr(|Prof. Alan Perlis↓Chairman, Department of Computer Science↓Yale University
.↓New Haven, Conn 06520|,Professor Perlis);

.ltr(|Professor Lawrence H. Landweber↓Chairman, Computer Sciences Department
.↓University of Wisconsin - Madison↓1210 West Dayton Street↓Madison, Wisconsin 53706|,Professor Landweber);

.ltr(|Professor Jack Minker↓Chairman, Department of Computer Science↓University of Maryland
.↓College Park, Maryland 20742|,Jack);

.ltr(|Prof. S.D. Conte↓Chairman, Department of Computer Science↓Mathematical Sciences Building; Room 442
.↓Purdue University↓West Lafayette, Indiana 47907|,Professor Conte);

.ltr(|Mr. Sidney L. Mantler↓Thomas J. Watson Research Center↓P.O. Box 218
.↓Yorktown Heights, New York 10598|,Mr. Mantler);
.end