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∂AIL Prof. H. Yamada↓Department of Information Science
↓Faculty of Science↓University of Tokyo↓Tokyo, Japan∞
Dear Professor Yamada:

	I am happy to recommend Professor Shigeru Igarashi for a
Professorship in the Department of Information Science at Tokyo
University.  The main basis of my recommendation is Igarashi's
work in the mathematical structure of computer programs as
associated with the problem of proving that programs meet their
specifications.  Igarashi's PhD dissertation in 1964 was one
of the earliest papers in this field, and the approach he
took at that time owed almost nothing to the small amount of
work that had been done previously.
I consider his work in mathematical theory of computation the
best done and Japan and in sustained productivity he is in
the same class as Rod Burstall and Zohar Manna.

	We were fortunate in having him visit the Stanford 
Artificial Intelligence Laboratory for a year on two separate
occasions and became familiar with his work and personality.
In addition to that, I visited Kyoto University for three months
in the Spring of 1975 and had the opportunity to observe how
he helped the younger people there and guided their work.

	I don't have Igarashi's bibliography in front of me, but
the paper with which I am most familiar is the one in which he
discussed how to extend first order logic so as to include
Scott's theory of computable functions.  This is a difficult
and important problem
for mathematical theory of computation,
and I don't think Igarashi completely solved it, but
his paper represents the only progress so far published.

	I hope this belated letter will help in making your decision.

.sgn