## Happenings – 2012 Aug 4

20 Aug 2012 Edit: The differential equations book did have material on Heaviside’s operational calculus!

What I’ve got for today’s post is little more than headlines. Perhaps what I need today is a ticker tape running across the bottom of my homepage.

Roger Federer and Andy Murray will play for gold and silver medals tomorrow. While I’ll be rooting for Roger, I think I will not be unhappy if Andy takes the gold. Come on… he’s competing in front of a home crowd and it would mean so much to him to win it there.

There were no further earthquakes in my vicinity in July, although there has been one so far in August. (I am counting only magnitude 2.5 or greater.) The total in July, then, remains at 11. We had 9 in June, and 11 in May. I think that’s enough counting… the next time somebody tells me that they are predicting a magnitude 2.5 earthquake in the Bay Area in the next 2 weeks, I’ll tell them I’m predicting 5, give or take.

For this Monday evening, I have one post through stage III – the mathematics is done, but the lecture is not. This, at last, is the post about the final tableau of a linear programming problem. As I have said before, the final tableau contains useful information… but it would be nice to derive it from the initial tableau and the optimal solution – the latter of which Mathematica® finds easily. Well, I can show you how to do that.

But that is not my 1st choice for Monday’s post. I would like to put out the penultimate regression post – at least for the foreseeable future. It’s not even in stage III – all I have is an outline – but it should be an easy post to write. (Famous last words.) Oddly enough, one of the challenges is coming up with a good title; I’m still struggling with it.

Why? In a nutshell, if a regression t-statistic fails to reject the null hypothesis – this coefficient is zero – then the theorem that justified using the t-statistic isn’t applicable. Talk about a dilemma… paradox… catch-22! How do I capture this in the title?

As for last Monday’s post, it was surprisingly popular. The blog as a whole got 440 hits on Monday, and the post itself got 350 in its 1st 2 days. That’s nice.

In my spare time, I finished reading Ian Stewart’s “in pursuit of the unknown: 17 equations that changed the world”. In his chapter on Maxwell’s equations, he said that the urban myth that carrots are good for your eyesight was misinformation from World War II – deliberately spread by the British to offer the Germans some explanation as to why their bombers were being detected so far out. It was actually radar, of course, not Brits doped up on beta carotene.

Anyway, I needed to check that. I was glad to see Snopes agrees with Stewart. if you’ve never used this website, it’s a handy antidote to all those miraculous stories people spread via e-mail.

The final 2 of the 4 books I ordered came in after last week’s diary post. The bad news is that the differential equations book had nothing in it about Heaviside’s methodology – replaced by Laplace transforms around 1950 – so I’ll have to piece it together from the 2 books I have.

20 Aug 2012 Edit: The differential equations book did have material – good stuff, too – on Heaviside’s operational calculus!

In addition to finishing off Stewart’s book, I have been reading – not working – Strogatz’ “nonlinear dynamics and chaos”, and also Roman’s “introduction to the mathematics of finance”.

The Strogatz book looks wonderful – I’m on page 348 of 453. And the finance book looks like the place to start – for me at least. (I’ve got 3 other books on mathematical finance, but this was the one to start with.)

And that’s it for now. I have no idea where the time went this morning, but let me go do math.