Log24

Tuesday, April 19, 2016

The Folding

Filed under: General,Geometry — m759 @ 2:00 PM

(Continued

A recent post about the eightfold cube  suggests a review of two
April 8, 2015, posts on what Northrop Frye called the ogdoad :

As noted on April 8, each 2×4 "brick" in the 1974 Miracle Octad Generator
of R. T. Curtis may be constructed by folding  a 1×8 array from Turyn's
1967 construction of the Golay code.

Folding a 2×4 Curtis array yet again  yields the 2x2x2 eightfold cube .

Those who prefer an entertainment  approach to concepts of space
may enjoy a video (embedded yesterday in a story on theverge.com) —
"Ghost in the Shell: Identity in Space." 

Thursday, August 21, 2014

The Folding

Filed under: General — m759 @ 2:00 AM

See Madeleine + Folded.

An illustration (click to enlarge) —

Related material: Posts from the above upload date, 10/1/10.

Friday, December 2, 2016

When to Fold ’Em

Filed under: General — m759 @ 12:00 AM

See The Folding in this journal.

Friday, April 8, 2016

Ogdoads by Curtis

Filed under: General,Geometry — Tags: , — m759 @ 12:25 PM

As was previously noted here, the construction of the Miracle Octad Generator
of R. T. Curtis in 1974 involved his "folding" the 1×8 octads constructed in 1967
by Turyn into 2×4 form.

This resulted in a way of picturing a well-known correspondence (Conwell, 1910)
between partitions of an 8-set and lines of the projective 3-space PG(3,2).

For some background related to the "ogdoads" of the previous post, see
A Seventh Seal (Sept. 15, 2014).

Thursday, October 30, 2014

Mimicry

Filed under: General — m759 @ 5:09 PM

This journal Tuesday,  Oct. 28, 2014, at 5 PM ET:

“What is a tai chi master, and what is it that he unfolds?”

From an earlier post, Hamlet’s father’s ghost
on “the fretful porpentine”:

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 combinèd 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.”

Galway Kinnell:

“I roll
this way and that in the great bed, under
the quilt
that mimics this country of broken farms and woods”

— “The Porcupine”

For quilt-block designs that do not mimic farms or woods,
see the cover of Diamond Theory .  See also the quotations
from Wallace Stevens linked to in the last line of yesterday’s
post in memory of Kinnell.

“… a bee for the remembering of happiness” — Wallace Stevens

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, March 19, 2009

Thursday March 19, 2009

Filed under: General,Geometry — m759 @ 11:07 AM
Two-Face

The Roman god Janus, from Wikipedia

[Note: Janus is Roman, not Greek, and
the photo is from one “Fubar Obfusco”]

 
The Roman god Janus, from Barry Mazur at Harvard
 Click on image for details.

From January 8:

Religion and Narrative, continued:

A Public Square

In memory of
Richard John Neuhaus,
who died today at 72:

“It seems, as one becomes older,
That the past has another pattern,
   and ceases to be a mere sequence….”

— T. S. Eliot, Four Quartets

A Walsh function and a corresponding finite-geometry hyperplane

Click on image for details.

See also The Folding.

Posted 1/8/2009 7:00 PM

Context:

Notes on Mathematics and Narrative

(entries in chronological order,
March 13 through 19)

Thursday, January 8, 2009

Thursday January 8, 2009

Filed under: General,Geometry — m759 @ 7:00 PM

A Public Square

In memory of
Richard John Neuhaus,
who died today at 72:

“It seems, as one becomes older,
That the past has another pattern,
   and ceases to be a mere sequence….”

— T. S. Eliot, Four Quartets

A Walsh function and a corresponding finite-geometry hyperplane

See also The Folding.

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.'”

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