Log24

Thursday, August 31, 2017

A Conway-Norton-Ryba Theorem

Filed under: General,Geometry — Tags: , — m759 @ 1:40 pm

In a book to be published Sept. 5 by Princeton University Press,
John Conway, Simon Norton,  and Alex Ryba present the following
result on order-four magic squares —

A monograph published in 1976, “Diamond Theory,” deals with
more general 4×4 squares containing entries from the Galois fields
GF(2), GF(4), or GF(16).  These squares have remarkable, if not
“magic,” symmetry properties.  See excerpts in a 1977 article.

See also Magic Square and Diamond Theorem in this  journal.

Monday, October 16, 2017

Highway 61 Revisited

Filed under: G-Notes,General,Geometry — Tags: , , , — m759 @ 10:13 am

"God said to Abraham …." — Bob Dylan, "Highway 61 Revisited"

Related material — 

See as well Charles Small, Harvard '64, 
"Magic Squares over Fields" —

— and Conway-Norton-Ryba in this  journal.

Some remarks on an order-five  magic square over GF(52):

"Ultra Super Magic Square"

on the numbers 0 to 24:

22   5   18   1  14
  3  11  24   7  15
  9  17   0  13  21
10  23   6  19   2
16   4  12  20   8

Base-5:

42  10  33  01  24 
03  21  44  12  30 
14  32  00  23  41
20  43  11  34  02
31  04  22  40  13 

Regarding the above digits as representing
elements of the vector 2-space over GF(5)
(or the vector 1-space over GF(52)) 

All vector row sums = (0, 0)  (or 0, over GF(52)).
All vector column sums = same.

Above array as two
orthogonal Latin squares:
   
4 1 3 0 2     2 0 3 1 4
0 2 4 1 3     3 1 4 2 0 
1 3 0 2 4     4 2 0 3 1         
2 4 1 3 0     0 3 1 4 2
3 0 2 4 1     1 4 2 0 3

— Steven H. Cullinane,
      October 16, 2017

Thursday, September 14, 2017

Found …

Filed under: General,Geometry — m759 @ 11:02 pm

( A sequel to the previous post, Lost )

From a link, "A Little Boy and a Little Girl," found in a Log24
search for Andersen + Atlantic

"A few flakes of snow were falling, and one of them, rather larger
than the rest, alighted on the edge of one of the flower boxes.
This snow-flake grew larger and larger, till at last it became
the figure of a woman, dressed in garments of white gauze,
which looked like millions of starry snow-flakes linked together.
She was fair and beautiful, but made of ice—
shining and glittering ice." — "The Snow Queen"

Related material —

Analogue of the little boy from "The Snow Queen" in "Equals" (2015) —

"Nice piece of ice." — Brendan Fraser in
"The Mummy: Tomb of the Dragon Emperor" (2008).

See also the concept that everything adds up to nothing in
"The Zero Theorem" (2013) 

and the Conway-Norton-Ryba theorem (2017).

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