Laurence Kirby Professor of Mathematics, Baruch College of the City University of New York
Plimpton 322: The Ancient Roots of Modern Mathematics ... a 33-minute video documentary

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             Released 6 December 2011
About the movie: With New York City as backdrop, Laurence Kirby takes viewers on a tour of our mathematical debt to ancient cultures in the Middle East, Asia and Africa. We witness their ideas still playing crucial roles in our society and 21st-century technology. At the center of the film is a 4,000-year-old cuneiform tablet known as Plimpton 322, which was excavated in Iraq around 1920 and now has its home in New York.

My office is Room 6-222 in the Vertical Campus of  Baruch College, my office phone number is (646) 312-4127, and you can  send me e-mail .
A Hydra With Jeff Paris, I invented THE HYDRA GAME in 1982. Thanks to Andrej Bauer, you can now play the Hydra game online. (Click on "Try the game online" near the bottom of the page.)
CUNY Math Blog: South Indian Cuisine with Professor Laurence Kirby

Two views of the beginning of the process of generating all finite sets:

Building up the finite sets The first 33 sets, adductive form
 Click here for another, higher resolution picture...        Click here for a related animation (size 250K)
For more information, see my article A hierarchy of hereditarily finite sets (893K pdf file)

Click on the image at right for a mathematical puzzle-poem. Only 4 people have ever solved it. Be the fifth person to send me the solution!

Tree: a mathematical puzzle-poemTree

Three articles in Mathematical Logic Quarterly: Ordinal operations on graph representations of sets (2013)
Substandard models of finite set theory (2010)
Addition and multiplication of sets (2007)

On Goodstein sequences and hydras: Accessible Independence Results for Peano Arithmetic (with Jeff Paris, 1982)

I received a B.A. and M.A. from Cambridge University, and a Ph.D. from Manchester University in 1977. After spells in Paris and Princeton, I joined Baruch College as a professor in 1982.
My research area is Mathematical Logic, and the philosophical background to my research has been the question:
What is the relationship between language and reality?
(assuming there is such a thing as reality).
I have studied this question in the technical context of the formal "language" of arithmetic, and the "reality" of the structure of the natural numbers (0,1,2,3, etc.) that arithmetic purports to describe. In fact, no reasonable language can capture this reality exactly and uniquely: there are always "non-standard" structures that do the job too. These are the models of arithmetic.
More recently I have explored more general ways to erode the distinction between language ("the dress of thought" -- Dr. Johnson) and the thought it dresses, in a philosophical study of logical principles for reasoning about natural objects, as opposed to the abstract objects of mathematics. You can read about this in my article,
 Steps towards a logic of natural objects.
Questions about natural objects and feasibility led to my current investigations into finite sets, and the pictures above.
I explore the same general questions in poetry, writing, song and music,
in the person of my alter ego, T. G. Vanini .

 Baruch College Mathematics Department 
  Logic in the New York metropolitan area