This is a copy of the Guidi Notes for Gian-Carlo Rota’s Probability course at MIT the last time Rota gave the course. A copy of the Rota-Baclawski text used as course material can also be downloaded here.
Gian-Carlo Rota’s Combinatorial Theory Course: The Guidi Notes
June 13, 2016 by
This is a copy of the Guidi Notes for Gian-Carlo Rota’s famous Combinatorial Theory course at MIT taken the last time Rota taught the course.
Counting Direct-sum Decompositions
March 28, 2016 by
This paper uses elementary methods to derive the formulas for and to tablulate (in the case q = 2) two related q-analogs of the Stirling numbers of the second kind and the Bell numbers for direct-sum decompositions (vector space analogs of set partitions) of a finite vector space over a finite field with q elements.
The Joy of Hets (talk slides)
February 29, 2016 by
These are the slides from a talk on the role of heteromorphisms (hets) in category theory given at the Category Theory Seminar at NYU on January 13, 2016.
On Vectorial Marginal Products and Modern Property Theory
December 20, 2015 by
When proposing some unorthodox theory, like the modern labor theory of property, orthodox economists always say: “Show me the math!” Well, here it is.
The Existence-Information Duality
October 30, 2015 by
The development of the logic of partitions (dual to the usual Boolean logic of subsets) and logical information theory bring out a fundamental duality between existence (e.g., elements of a subset) and information (e.g., distinctions of a partition). This leads in a more meta-physical vein to two different conceptions of reality, one of which provides the realistic interpretation of quantum mechanics.
Partition Logic talk slides Ljubljana
September 23, 2015 by
Slides from talk on Partition Logic at University of Ljubljana Sept. 8, 2015.
On the Objective Indefiniteness Interpretation of Quantum Mechanics
August 28, 2015 by
Classical physics and quantum physics suggest two different meta-physical conceptions of reality: the classical notion of a objectively definite reality “all the way down,” and the quantum conception of an objectively indefinite type of reality. Part of the problem of interpreting quantum mechanics (QM) is the problem of making sense out of an objectively indefinite reality. Our sense-making strategy is to follow the math by showing that the mathematical way to describe indefiniteness is by partitions (quotient sets or equivalence relations).
Mac Lane, Bourbaki, and Adjoints Redux
June 16, 2015 by
Saunders Mac Lane famously said that Bourbaki (in the person of Pierre Samuel) “just missed” developing the notion of an adjunction in 1948 a decade before Daniel Kan. When adjoints are defined using heteromorphisms or chimera morphisms (first done by Bodo Pareigis in 1970), then indeed Samuel was only a now-simple dualization away from defining adjoints. Since the heteromorphic treatment allows adjunctions to be factored into two, in general, independent universal mapping properties (UMPs), we also pose the question as to whether adjunctions or UMPs should be considered as category theory’s most important concept. It seems Mac Lane and most orthodox category theorists would say adjunctions but Grothendieck among others would say UMPs stated using representable functors.
On Adjoint and Brain Functors
June 16, 2015 by
We give a heterodox treatment of adjoints using heteromorphisms (object-to-object morphisms between objects of different categories) that parses an adjunction into two separate parts (left and right representations of heteromorphisms). Then these separate parts can be recombined in a new way to define a cognate concept, the brain functor, to abstractly model the functions of perception and action of a brain. This is a preprint of the paper coming out in Axiomathes.