tingilinde

betty moore shannon

Claude Shannon's wife was also a mathematician.

a tip of the hat to Jim

 

the art of chalkboards

Probably a fun book

 

 

what data can't do

Commentary by Hannah Fry on two books on the subject.  (via The New Yorker)

 

 

 

numberphile on fluids

Numberphile often gives intuitive tastes of math and related subjects that often require serious work in college.  Here's a fine three part series featuring Tom Crawford of Oxford.   A nice example of equation → approximation → real world example (with more approximations) 

 

The Navier-Stokes Equation

The Reynolds Number



River Water

newton and Pi

fun with ropes - a bit of topology

(skip to about 3m if you want to see the demos and the explanation)

pi day

At least in the US..  the rest of the world is on the more accurate 22/7..

Pi
by Wisława Szymborska

The admirable number pi:
three point one four one.
All the following digits are also initial,
five nine two because it never ends.
It can’t be comprehended six five three five at a glance,
eight nine by calculation,
seven nine or imagination,
not even three two three eight by wit, that is, by comparison
four six to anything else
two six four three in the world.
The longest snake on earth calls it quits at about forty feet.
Likewise, snakes of myth and legend, though they may hold out a bit longer.
The pageant of digits comprising the number pi
doesn’t stop at the page’s edge.
It goes on across the table, through the air,
over a wall, a leaf, a bird’s nest, clouds, straight into the sky,
through all the bottomless, bloated heavens.
Oh how brief — a mouse tail, a pigtail — is the tail of a comet!
How feeble the star’s ray, bent by bumping up against space!
While here we have two three fifteen three hundred nineteen
my phone number your shirt size the year
nineteen hundred and seventy-three the sixth floor
the number of inhabitants sixty-five cents
hip measurement two fingers a charade, a code,
in which we find hail to thee, blithe spirit, bird thou never wert
alongside ladies and gentlemen, no cause for alarm,
as well as heaven and earth shall pass away,
but not the number pi, oh no, nothing doing,
it keeps right on with its rather remarkable five,
its uncommonly fine eight,
its far from final seven,
nudging, always nudging a sluggish eternity
to continue.

 

a (much) better flat map

Topology tells you a sphere can't be perfectly flatted - and that's a problem with 2d world maps.  Now Richard Gott,  Dave Goldberg  and Robert Vanderbei have used a new mathematical technique that turns the sphere into a two sided flat map with adjustments made to the features on both sides.  Here's a descrption.

a tip of the hat to Greg

And the paper is on the arXiv

 

 

Flat Maps that improve on the Winkel Tripel

J. Richard Gott III1, David M. Goldberg2, and Robert J. Vanderbei3 1. Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA
2. Department of Physics, Drexel University, Philadelphia, PA, USA
3. Department of Operations Research, Princeton University, Princeton, NJ, USA

 

ABSTRACT
Goldberg & Gott (2008) developed six error measures to rate flat map projections on their verisimilitude to the sphere: Isotropy, Area, Flexion, Skewness, Distances, and Boundary Cuts. The first two depend on the metric of the projection, the next two on its first derivatives. By these criteria, the Winkel Tripel (used by National Geographic for world maps) was the best scoring of all the known projections with a sum of squares of the six errors of 4.563, normalized relative to the Equirectangular in each error term. We present here a useful Gott-Wagner variant with a slightly better error score of only 4.497. We also present a radically new class of flat double-sided maps (like phonograph records) which have correct topology and vastly improved error scores: 0.881 for the azimuthal equidistant version. We believe it is the most accurate flat map of Earth yet. We also show maps of other solar system objects and sky maps.

 

 

 

 

 

 

johnny carson explains a hat problem

Johnny Carson takes on a simple version of the colored hat problem.  I can't imagine an entertainment show doing anything like this now.

the riemann hypothesis

A very clear discussion of the Riemann Hypothesis  - one of the most important conjectures - maybe the most important - in math.