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CLEO - Circuits Learned by Example Online
On our site you will find over 250 examples covering a two-semester course sequence in engineering linear circuit analysis, including AC and DC circuits, phasors, op amps, transients, power, and Laplace-based analysis. The examples are designed by electrical engineering professors who collectively have 15 years experience teaching circuit analysis. You can browse and search for examples that are similar to your own homework problems, giving you the practice and instruction you’re looking for. Once you work an example as a practice problem, you can check your answer to get quick feedback about how well you can apply what you have learned in class. When you need help working the example, watch a short video in which the professor works the example in detail and explains each step along the way. If you have speakers or headphones, be sure they are turned on so you can follow the professor’s audio explanation, or you can watch the captioned version.
Gyre&Gimble
This blog has moved to a new site: http://www.abstractmath.org/Word%20Press/ Most of the articles that were on this site are now on the new site with the same name. The series of articles entitled Definitions into Mathematical Objects have been consolidated into an article entitled Introduction to Forms .
Division by Zero
Last weekend I was in Lexingon, Kentucky for MathFest 2011 . I had a very nice time and saw some very good talks. I thought, just for fun, that I’d share a couple of juicy mathematical tidbits I learned. Fibonacci numbers and the golden ratio
A few days ago, Endre Szemerédi was awarded the 2012 Abel prize “for his fundamental contributions to discrete mathematics and theoretical computer science, and in recognition of the profound and lasting impact of these contributions on additive number theory and ergodic theory.” The full citation for the prize may be found here , and the written notes for a talk given by Tim Gowers on Endre’s work at the announcement may be found here (and video of the talk can be found here ). As I was on the Abel prize committee this year, I won’t comment further on the prize, but will instead focus on what is arguably Endre’s most well known result, namely Szemerédi’s theorem on arithmetic progressions : Theorem 1 (Szemerédi’s theorem) Let be a set of integers of positive upper density, thus , where . Then contains an arithmetic progression of length for any
What’s new
In the previous post we learned that it is possible to recover the center of a ring from its category of left modules (as an -enriched category). For commutative rings, this justifies the idea that it is sensible to study a ring by studying its modules (since the modules know everything about the ring). For noncommutative rings, the situation is more interesting. Two rings are said to be Morita equivalent if the categories are equivalent as
Annoying Precision
The Unapologetic Mathematician
A comment just came in on my short rant about electromagnetism texts . Dripping with condescension, it states: Here’s the fundamental reason for your discomfort: as a mathematician, you don’t realize that scalar and vector potentials have *no physical significance* (or for that matter, do you understand the distinction between objects of physical significance and things that are merely convenient mathematical devices?). It really doesn’t matter how scalar and vector potentials are defined, found, or justified, so long as they make it convenient for you to work with electric and magnetic fields, which *are* physical (after all, if potentials were physical, gauge freedom would make no sense). On rare occasions (e.g.
Steven Weinberg has a new article in The New York Review of Books on The Crisis of Big Science , which is based on a talk he gave this past January at the American Astronomical Society meeting in Austin (for some discussion of this, see here and here ). Weinberg is rather gloomy about prospects for particle physics, seeing dim prospects for a new generation of particle accelerators, especially in the US. He goes over the sorry story of the SSC, which he was deeply involved in, and worries that the same thing is happening to the James Webb Space Telescope project. He argues that progress is particle physics will be difficult without going to higher energies:
Not Even Wrong
The n-Category Café
Where: Paris, Ecole Normale Supérieure (45, rue d’Ulm, 75005). Salle “W” (staircase B, 3d floor): May 17, 31 and June 14 in the morning. Salle Beckett (ground floor): June 14 afternoon.