Log24

Wednesday, August 21, 2019

Time Fold Revisited

Filed under: General — m759 @ 12:01 AM

British cover (2011) for 'From Eternity to Here,' by Sean Carroll

(Oneworld Publications, Jan. 3, 2011)

Compare and contrast with an illustration
from "Time Fold," a webpage of Oct. 10, 2003 —

See also the Squarespace logo:

Thursday, July 28, 2016

The Giglmayr Foldings

Filed under: General,Geometry — m759 @ 1:44 PM

Giglmayr's transformations (a), (c), and (e) convert
his starting pattern

  1    2   5   6
  3    4   7   8
  9  10 13 14
11  12 15 16

to three length-16 sequences. Putting these resulting
sequences back into the 4×4 array in normal reading
order, we have

  1    2    3    4        1   2   4   3          1    4   2   3
  5    6    7    8        5   6   8   7          7    6   8   5 
  9  10  11  12      13 14 16 15       15 14 16 13
13  14  15  16       9  10 12 11        9  12 10 11

         (a)                         (c)                      (e)

Four length-16 basis vectors for a Galois 4-space consisting
of the origin and 15 weight-8 vectors over GF(2):

0 0 0 0       0 0 0 0       0 0 1 1       0 1 0 1
0 0 0 0       1 1 1 1       0 0 1 1       0 1 0 1 
1 1 1 1       0 0 0 0       0 0 1 1       0 1 0 1
1 1 1 1       1 1 1 1       0 0 1 1       0 1 0 1 .

(See "Finite Relativity" at finitegeometry.org/sc.)

The actions of Giglmayr's transformations on the above
four basis vectors indicate the transformations are part of
the affine group (of order 322,560) on the affine space
corresponding to the above vector space.

For a description of such transformations as "foldings,"
see a search for Zarin + Folded in this journal.

Sunday, August 31, 2014

Sunday School

Filed under: General,Geometry — Tags: — m759 @ 9:00 AM

The Folding

Cynthia Zarin in The New Yorker , issue dated April 12, 2004—

“Time, for L’Engle, is accordion-pleated. She elaborated,
‘When you bring a sheet off the line, you can’t handle it
until it’s folded, and in a sense, I think, the universe can’t
exist until it’s folded — or it’s a story without a book.’”

The geometry of the 4×4 square array is that of the
3-dimensional projective Galois space PG(3,2).

This space occurs, notably, in the Miracle Octad Generator (MOG)
of R. T. Curtis (submitted to Math. Proc. Camb. Phil. Soc.  on
15 June 1974).  Curtis did not, however, describe its geometric
properties. For these, see the Cullinane diamond theorem.

Some history: 

Curtis seems to have obtained the 4×4 space by permuting,
then “folding” 1×8 binary sequences into 4×2 binary arrays.
The original 1×8 sequences came from the method of Turyn
(1967) described by van Lint in his book Coding Theory
(Springer Lecture Notes in Mathematics, No. 201 , first edition
published in 1971). Two 4×2 arrays form each 4×4 square array
within the MOG. This construction did not suggest any discussion
of the geometric properties of the square arrays.

[Rewritten for clarity on Sept. 3, 2014.]

Thursday, July 8, 2010

Toronto vs. Rome

Filed under: General,Geometry — m759 @ 9:00 PM

or: Catullus vs. Ovid

(Today's previous post, "Coxeter vs. Fano,"
might also have been titled "Toronto vs. Rome.")

ut te postremo donarem munere mortis

Catullus 101

Explicatio

Unfolding

Image by Christopher Thomas at Wikipedia
Unfolding of a hypercube and of a cube —

http://www.log24.com/log/pix10A/100506-Hcube_fold.gif

Image--Chess game from 'The 
Seventh Seal'

The metaphor for metamorphosis no keys unlock.
— Steven H. Cullinane, "Endgame"

The current New Yorker  has a translation of
  the above line of Catullus by poet Anne Carson.
According to poets.org, Carson "attended St. Michael's College
at the University of Toronto and, despite leaving twice,
received her B.A. in 1974, her M.A. in 1975 and her Ph.D. in 1981."

Carson's translation is given in a review of her new book Nox.

The title, "The Unfolding," of the current review echoes an earlier
New Yorker  piece on another poet, Madeleine L'Engle—

Cynthia Zarin in The New Yorker, issue dated April 12, 2004–

“Time, for L’Engle, is accordion-pleated. She elaborated,
‘When you bring a sheet off the line, you can’t handle it
until it’s folded, and in a sense, I think, the universe can’t
exist until it’s folded– or it’s a story without a book.’”

(See also the "harrow up" + Hamlet  link in yesterday's 6:29 AM post.)

Monday, December 22, 2008

Monday December 22, 2008

Filed under: General,Geometry — Tags: , — m759 @ 9:00 PM

The Folding

Hamlet, Act 1, Scene 5

Ghost:

“I could a tale unfold whose lightest word
Would harrow up thy soul, freeze thy young blood,
Make thy two eyes, like stars, start from their spheres,
Thy knotted and combined locks to part
And each particular hair to stand on end,
Like quills upon the fretful porpentine:
But this eternal blazon must not be
To ears of flesh and blood. List, list, O, list!”

This recalls the title of a piece in this week’s New Yorker:”The Book of Lists:
Susan Sontag’s early journals
.” (See Log24 on Thursday, Dec. 18.)

In the rather grim holiday spirit of that piece, here are some journal notes for Sontag, whom we may imagine as the ghost of Hanukkah past.

There are at least two ways of folding a list (or tale) to fit a rectangular frame.The normal way, used in typesetting English prose and poetry, starts at the top, runs from left to right, jumps down a line, then again runs left to right, and so on until the passage is done or the bottom right corner of the frame is reached.

The boustrophedonic way again goes from top to bottom, with the first line running from left to right, the next from right to left, the next from left to right, and so on, with the lines’ directions alternating.

The word “boustrophedon” is from the Greek words describing the turning, at the end of each row, of an ox plowing (or “harrowing”) a field.

The Tale of
the Eternal Blazon

by Washington Irving

Blazon meant originally a shield, and then the heraldic bearings on a shield.
Later it was applied to the art of describing or depicting heraldic bearings
in the proper manner; and finally the term came to signify ostentatious display
and also description or record by words or other means. In Hamlet, Act I. Sc. 5,
the Ghost, while talking with Prince Hamlet, says:

‘But this eternal blazon
must not be
To ears of flesh and blood.’

Eternal blazon signifies revelation or description of things pertaining to eternity.”

Irving’s Sketch Book, p. 461

By Washington Irving and Mary Elizabeth Litchfield, Ginn & Company, 1901

Related material:

Folding (and harrowing up)
some eternal blazons —

The 16 Puzzle: transformations of a 4x4 square
These are the foldings
described above.

They are two of the 322,560
natural ways to fit
the list (or tale)
“1, 2, 3, … 15, 16”
into a 4×4 frame.

For further details, see
The Diamond 16 Puzzle.

Moral of the tale:

Cynthia Zarin in The New Yorker, issue dated April 12, 2004–

“Time, for L’Engle, is accordion-pleated. She elaborated, ‘When you bring a sheet off the line, you can’t handle it until it’s folded, and in a sense, I think, the universe can’t exist until it’s folded– or it’s a story without a book.'”

Saturday, May 13, 2006

Saturday May 13, 2006

Filed under: General — m759 @ 4:00 PM

ART WARS continued…

A Fold in Time

From May 13, Braque’s birthday, 2003:


Braque


Above: Braque and tesseract

“The senses deform, the mind forms.  Work to perfect the mind.  There is no certitude but in what the mind conceives.”

— Georges Braque, Reflections on Painting, 1917

Those who wish to follow Braque’s advice may try the following exercise from a book first published in 1937:

The image “http://www.log24.com/theory/images/Carmichael440ex.gif” cannot be displayed, because it contains errors.

Hint: See the above picture of
Braque and the construction of
a tesseract.

Related material:

Storyline and Time Fold
(both of Oct. 10, 2003),
and the following–

“Time, for L’Engle, is accordion-pleated. She elaborated, ‘When you bring a sheet off the line, you can’t handle it until it’s folded, and in a sense, I think, the universe can’t exist until it’s folded– or it’s a story without a book.'”

Cynthia Zarin on Madeleine L’Engle,
“The Storyteller,” in The New Yorker,
issue dated April 12, 2004

Powered by WordPress