Category: Mathematics

Bookmarked Information theory in living systems, methods, applications, and challenges. by R. A. Gatenby, B. R. FriedenR. A. Gatenby, B. R. Frieden (Bull Math Biol. 2007 Feb;69(2):635-57. Epub 2006 Nov 3.)

Living systems are distinguished in nature by their ability to maintain stable, ordered states far from equilibrium. This is despite constant buffeting by thermodynamic forces that, if unopposed, will inevitably increase disorder. Cells maintain a steep transmembrane entropy gradient by continuous application of information that permits cellular components to carry out highly specific tasks that import energy and export entropy. Thus, the study of information storage, flow and utilization is critical for understanding first principles that govern the dynamics of life. Initial biological applications of information theory (IT) used Shannon's methods to measure the information content in strings of monomers such as genes, RNA, and proteins. Recent work has used bioinformatic and dynamical systems to provide remarkable insights into the topology and dynamics of intracellular information networks. Novel applications of Fisher-, Shannon-, and Kullback-Leibler informations are promoting increased understanding of the mechanisms by which genetic information is converted to work and order. Insights into evolution may be gained by analysis of the the fitness contributions from specific segments of genetic information as well as the optimization process in which the fitness are constrained by the substrate cost for its storage and utilization. Recent IT applications have recognized the possible role of nontraditional information storage structures including lipids and ion gradients as well as information transmission by molecular flux across cell membranes. Many fascinating challenges remain, including defining the intercellular information dynamics of multicellular organisms and the role of disordered information storage and flow in disease.

PMID: 17083004 DOI: 10.1007/s11538-006-9141-5

Paul Halmos on Prerequisites

Definitely the quote of the day:

…[the reader] should not be discouraged, if on first reading of section 0, he finds that he does not have the prerequisites for reading the prerequisites.

Paul Halmos (1916 – 2006, Hungarian-born American mathematician
in Measure Theory (1950)

 

This is essentially the mathematician’s equivalent of the adage “Fake it ’til you make it.”

Riemann’s On the Hypotheses Which Lie at the Foundations of Geometry

One must be truly enamored of the internet that it allows one to find and read a copy of Bernhard Riemann’s doctoral thesis Habilitation Lecture (in English translation) at the University of Göttingen from 1854!

His brief paper has created a tsunami of mathematical work and research in the ensuing 156 years. It has ultimately become one of the seminal works in the development of the algebra and calculus of n-dimensional manifolds.

Nicholas Bourbaki and Serge Lang

Replied to Scientific Fiction – The Bourbaki Mystery by Sue Vazakas (The Sheridan Libraries Blog)

In the 1930s, a French mathematician began writing journal articles and books. His name was Nicolas Bourbaki. He didn’t exist.

Bourbaki was and is actually a group of brilliant and influential mathematicians, mostly French but not all, whose membership changes but whose collective purpose remains the same: to write about mathematical topics they deem important. Between 1939 and 1967 “he” wrote a series of influential books about these selected topics, collectively called Elements of Mathematics.

A mysterious, mostly anonymous group of writers publishing momentous things under a single name is just really cool. But don’t try to read any of his stuff unless you are an expert mathematician.

Instead, read a wonderful story by novelist and award-winning chemist Carl Djerassi, called The Bourbaki Gambit. What do you think happens when a group of scientists, being discriminated against for various reasons, team up and use the “Bourbaki” approach to try to get their latest discovery taken seriously?

There’s an old mathematicians’ joke that goes like this:

Q: When did Nicholas Bourbaki quit writing books about mathematics?

A: When (t)he(y) realized that Serge Lang was only one person!

Terence Tao Teaching Real Analysis at UCLA this Fall

Holy cow! I discovered on Friday that Terence Tao, a Fields Medal winner, will be teaching a graduate level Real Analysis class this fall at UCLA.

Surprisingly, to me, it ony has 4 students currently enrolled!! Having won a Fields Medal in August 2006, this is a true shock, for who wouldn’t want to learn analysis from such a distinguished professor? Are there so few graduate students at UCLA who need a course in advanced analysis? I would imagine that there would be graduate students in engineering and even physics who might take such a course, but perhaps I’m wrong?

Most of his ratings on RateMyProfessors are actually fairly glowing; the one generally negative review was given for a topology class and generally seems to be an outlier.

On his own website in a section about the class and related announcements we seem to find the answer to the mystery about enrollment.  There he says:

 I intend this to be a serious course, focused on teaching the material in the course description.  As such, students who are taking or auditing the course out of idle curiosity or mathematical “sightseeing”, rather than to learn the basics of measure theory and integration theory, may be disappointed.  I would therefore prefer that frivolous enrollments in the class be kept to a minimum.

This is generally sound advice, but would even the most serious mathematical tourists really bother to make an attempt at such an advanced course? Why bother if you’re not going to do the work?!

Fans of the Mathematical Genealogy Project will be interested to notice that Dr. Tao is requiring his Ph.D. advisor’s text Real Analysis: Measure Theory, Integration, and Hilbert Spaces. He’s also recommending Folland‘s often used text as well, though if he really wanted to scare off the lookie-loos he could just say he’ll be using Rudin‘s text.

Baum’s Point Set Topology

Commenting only after reading to page 11, but having skimmed some other parts/sections, it’s a nice and condensed volume with most of the standard material on point set topology. It reads somewhat breezily, is well laid out, and isn’t bogged down with all the technicalities which those who haven’t seen any of this material before might have interest in. It seems better for those with some experience in axiomatic mathematics (I’ve always enjoyed Robert Ash’s A Primer of Abstract Mathematics for much of this material), but in my mind isn’t as clear or as thorough as James Munkres’ Topology, which I find in general to be a much better book, particularly for the self-learning crowd. The early problems and exercises are quite easy.

Given it’s 1964 publication date, most of the notation is fairly standard from a modern perspective and it was probably a bit ahead of it’s time from a pedagogical viewpoint.

Acquired The Mathematical Theory of Communication by Claude E. Shannon and Warren Weaver

Acquired The Mathematical Theory of Communication (The University of Illinois Press)
Scientific knowledge grows at a phenomenal pace--but few books have had as lasting an impact or played as important a role in our modern world as The Mathematical Theory of Communication, published originally as a paper on communication theory in the Bell System Technical Journal more than fifty years ago. Republished in book form shortly thereafter, it has since gone through four hardcover and sixteen paperback printings. It is a revolutionary work, astounding in its foresight and contemporaneity. The University of Illinois Press is pleased and honored to issue this commemorative reprinting of a classic.