Welcome to the 79th edition of the Carnival of Mathematics. By tradition, each edition begins with a bit of trivia about the number of the carnival.

Gold has atomic number 79, so this is the golden edition. There is an older tradition of calling 25th things silver, 50th things gold, etc. However, I propose switching to atomic numbers as this system is simpler and easier to look up. :)

Not only is 79 a prime number, it belongs to numerous categories of of prime numbers:

- Cousin
- Fortunate
- Lucky
- Happy
- Gaussian
- Higgs
- Kynea
- Permutable
- Pillai
- Regular
- Sexy

(Definitions here)

And now on to the posts.

**History**

Fëanor at JOST A MON presents Cipher, a history of zero through the Middle Ages.

**Historical wanderings**

Katie Sorene takes us on a stroll through ancient labyrinths on her blog Travel Blog – Tripbase.

Guillermo Bautista strolls through The Seven Bridges of Königsberg at Mathematics and Multimedia.

**Wandering**

Next we wander around a grid of dominoes. Jim Wilder presents The Domino Effect: An Elementary Approach to the Kruskal Count. Starting from this elementary post, you can wander into an investigation of coupling methods for Markov chains.

**Teaching**

Peter Rowlett discusses whether there is a generational gap between professors and students on his blog Travels in a Mathematical World.

Alexander Bogomolny from CTK Insights presents An Olympiad Problem for a Kindergarten Investigation. He gives a problem that is simple to describe and that has a simple but sophisticated solution.

**Media**

Mike Croucher shares a couple videos simulating pendulum waves, one in Maple and one in Mathematica.

Peter Rowlett explains why he supports Relatively Prime, Samuel Hansen’s Kickstarter project. Samuel Hansen has produced two mathematical podcasts and is now raising donations to fund the creation of a series of mathematical documentaries.

**Computing**

One of the most fundamental questions you can ask about a computer program is whether it stops. This may appear to be an easy task, yet there is a three-line program that no one knows whether it always terminates. Fëanor shared a link to Brian Hayes‘ commentary Don’t try to read this proof! on a recent proposed proof of the Collatz conjecture.

Applications often involve matrices that are too large to store directly. For an introduction to how large matrices are represented in computer memory, see Storing Banded Matrices for Speed from The NAG Blog. The post promises to be the first in a series.

**Next**

You can submit posts for the next Carnival of Mathematics here. Also, you can keep up with Carnival of Mathematics new and other mathematical tidbits by following CarnivalOfMath on Twitter.

Thank you for including my article.

Very nice topic!!

Thanks a lot=)

More “79” facts: For any 3217644767340672907899084554130 consecutive integers, 400440702414394285778534400000 will have 79 as a lowest prime factor. There were 79broadcasted episodes of the original “Star Trek” TV show. President Garfield died 79 days after entering being shot. In Jules Verne’s novel “Around the World in Eighty Days,” character Phileas Fogg actually succeeds his world tour trip in 79 days and wins his bet. Check out: http://www.primecurios.com.