## Birthday Greetings for Robert Tennent

Dear Bob -
I deeply regret that, I cannot be present for your birthday celebration at
MFPS. But I'd still like to offer my congratulations and express my
feelings.

Beginning at least as far back as your Ph.D. thesis, you have steadfastly
pursued a quest for the mathematical underpinnings of programming
languages. The result has been a series of profound papers, an influential
textbook, and two finely educated Ph.D. advisees, all testifying to the
belief that the design of programming languages can be a deeply rational
endeavor.

Your work is a peculiarly deep application of mathematics - not the usual
approach of translating a problem into mathematics and then using clever
theorems, but rather the seizing of the underlying organizing principles
of mathematics (especially category theory) to organize programming. It
is an inspiration to all of us who aspire to mathematically elegant
languages that support, rather than impede, the art of programming.

In addition to being a leader, however, you are a valued comrade - a
source of helpful encouragement and advice, invariably modest and
open-minded.

On your sixty-fifth birthday, I believe I speak for many when I thank you
for your ideas, your leadership, and your friendship.

All the best,

- John