Xah Math Blog Archive 2016-01 to 2016-02

Spare your arithmetic, never count the turns. Once, and a million!

—Shakespeare, in Cymbeline, Act II. Scene IV.

hard scifi 〈The Three-Body Problem〉 2015 Hugo Award

Three Body Problem  scifi book cover
The Three-Body Problem Buy at amazon

〈The Three-Body Problem〉 (三体) is a science fiction novel by the Chinese writer Liu Cixin.

An English translation by Ken Liu was published by Tor Books in 2014. It won the 2015 Hugo Award for Best Novel and was nominated for the 2014 Nebula Award for Best Novel.

read reviews on amazon, at Buy at amazon

black holes and gravitational wave, by Stephen Wolfram

three-body-problem-animation-1

[• Black Hole Tech? By Stephen Wolfram. At http://blog.stephenwolfram.com/2016/02/black-hole-tech/ , Accessed on 2016-02-23 ]

enjoyed this article. If for nothing, go look at the 3-body problem animation.

classic text book on algebraic geometry

This is the classic book on algebraic geometry.

Algebraic Geometry Robin Hartshorne cover
Algebraic Geometry by Robin Hartshorne. Buy at amazon

though, i recognized the name. He wrote another book:

Geometry Euclid and Beyond  Robin Hartshorne 0387986502
Geometry: Euclid and Beyond (Undergraduate Texts in Mathematics) by Robin Hartshorne. Buy at amazon

looking at amazon, apparently he wrote a few geometry texts. interesting is that he wrote one on Projective Geometry 〔 Foundations of Projective Geometry Buy at amazon

You might find many good geometry texts at Printed References On Plane Curves

… text books are too expensive. I think one can find lots of equivalents, cheap or free.

there's something wrong with pricing of text books in USA. The price tag is exorbitant. And i think the bottom line cause, is greed. No, am not inclined to blame anything or anyone just because they are successful or rich. But in the case of text books, i think indeed it's greed and schemes and made them so expensive, and universities have a lot to do with it.

educational institutions, such as universities, public or privately owned, as big organizations, they are not really doing the good they are supposed to do.

27 Lines on a Cubic Surface

27 Lines on a Cubic Surface – Greg Egan

[• 27 Lines on a Cubic Surface By John Baez. At http://blogs.ams.org/visualinsight/2016/02/15/27-lines-on-a-cubic-surface/ , Accessed on 2016-02-17 ]

Visual Dictionary of Special Plane Curves now has side panel for easy navigation.

Algorithmic Mathematical Art

Google DeepMind AI, AlphaGo to Challenge World Champion?

you may have heard, that Google DeepMind AI, AlphaGo, is doing a human vs machine, challenge a go champion Lee Se-dol.

They said they beat European Champion 5-0, so is now challenging a champion.

I got excited, thought it happened sooner than i expected. Spent some 30 min to read about it. Turns out, that “European champion” is only ranked 2 dan. (Pros are 9 dan)

(go playing is ranked by “dan”, or “level” if you will. Rather a bad system. The chess elo system is much better. But basically, the “dan” is meant to be the number of moves a stronger player can yield to the other for a even game. That is, if you are 4 dan, and i'm 1 dan, that means, if you give me handicap 3 stones (i play 3 moves first, usually on designated spots), then we would have a “even” game. That's the ideal, anyway. In reality, there are professional ranks of dan and armature ranks of dan. Armature 9 dan is something like pro 5 dan.)

so, the AlphaGo human vs machine is rather marketing deception. Am very disappointed and annoyed by the marketing tactics.

this “news”, is rather no news. The go human champion would beat google's AI 5-0.

Ladybug Video Game, Optimal Strategy

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