Log24

Wednesday, October 23, 2019

Overarching Narrative

Filed under: General — Tags: , — m759 @ 8:13 PM

In memory of a retired co-director of Galerie St. Etienne
who reportedly died on October 17 . . .

"It is difficult to mount encyclopedic exhibitions
without an overarching art-historical narrative…."

—  Jane Kallir, director of Galerie St. Etienne, in
https://www.tabletmag.com/jewish-arts-and-culture/
visual-art-and-design/269564/the-end-of-middle-class-art

An overarching narrative from the above death date

See as well the previous post 
and "Dancing at Lughnasa."

Thursday, October 17, 2019

Dance of the Fire Temple

Filed under: General — Tags: , , — m759 @ 10:13 AM

The previous post, Tetrahedron Dance, suggests a review of . . .

A figure from St. Patrick's Day 2004 that might
represent a domed  roof 

Inscribed Carpenter's Square:

In Latin, NORMA

 and a cinematic "Fire Temple" from 2019 

In related news . . .

Related background "e. e. cummings" in this  journal.

Tetrahedron Dance

Filed under: General — Tags: , , , — m759 @ 9:42 AM

John Lithgow in "The Tomorrow Man" (2019)

" connect the dots…."

IMAGE- 'The geometry of the dance' is that of a tetrahedron, according to Peter Pesic

Wednesday, October 9, 2019

The Joy of Six

Note that in the pictures below of the 15 two-subsets of a six-set,
the symbols 1 through 6 in Hudson's square array of 1905 occupy the
same positions as the anticommuting Dirac matrices in Arfken's 1985
square array. Similarly occupying these positions are the skew lines
within a generalized quadrangle (a line complex) inside PG(3,2).

Anticommuting Dirac matrices as spreads of projective lines

Related narrative The "Quantum Tesseract Theorem."

Monday, October 7, 2019

Oblivion

Filed under: General — Tags: , — m759 @ 1:09 PM

(A sequel to Simplex Sigillum Veri and 
Rabbit Hole Meets Memory Hole)

" Wittgenstein does not, however, relegate all that is not inside the bounds
of sense to oblivion. He makes a distinction between saying  and showing  
which is made to do additional crucial work. 'What can be shown cannot
be said,' that is, what cannot be formulated in sayable (sensical)
propositions can only be shown. This applies, for example, to the logical
form of the world, the pictorial form, etc., which show themselves in the
form of (contingent) propositions, in the symbolism, and in logical
propositions. Even the unsayable (metaphysical, ethical, aesthetic)
propositions of philosophy belong in this group — which Wittgenstein
finally describes as 'things that cannot be put into words. They make
themselves manifest. They are what is mystical' " (Tractatus  6.522).

Stanford Encyclopedia of Philosophy , "Ludwig Wittgenstein"

From Tractatus Logico-Philosophicus  by Ludwig Wittgenstein.

(First published in Annalen der Naturphilosophie ,1921.
English edition first published 1922 by Kegan Paul, Trench and Trübner. This translation first published 1961 by Routledge & Kegan Paul. Revised edition 1974.)

5.4541

The solutions of the problems of logic must be simple, since they set the standard of simplicity.

Men have always had a presentiment that there must be a realm in which the answers to questions are symmetrically combined — a priori — to form a self-contained system.

A realm subject to the law: Simplex sigillum veri.

Somehow, the old Harvard seal, with its motto "Christo et Ecclesiae ,"
was deleted from a bookplate in an archived Harvard copy of Whitehead's 
The Axioms of Projective Geometry  (Cambridge U. Press, 1906).

In accordance with Wittgenstein's remarks above, here is a new
bookplate seal for Whitehead, based on a simplex

Saturday, October 5, 2019

Midnight Landmarks

Filed under: General — Tags: , , — m759 @ 12:00 AM

Friday, September 27, 2019

Algebra for Schoolgirls

Filed under: General — Tags: , — m759 @ 8:37 AM

The 15 points of the finite projective 3-space PG(3,2)
arranged in tetrahedral form:

The letter labels, but not the tetrahedral form,
are from The Axioms of Projective Geometry , by
Alfred North Whitehead (Cambridge U. Press, 1906).

The above space PG(3,2), because of its close association with
Kirkman's schoolgirl problem, might be called "schoolgirl space."

Screen Rant  on July 31, 2019:

A Google Search sidebar this morning:

Apocalypse Soon!

Wednesday, September 25, 2019

Language Game

Filed under: General — Tags: , — m759 @ 9:28 AM

Previous posts now tagged Pyramid Game suggest

A possible New Yorker  caption:   " e . . . (ab) . . . (cd) . "

Caption Origins —

Playing with shapes related to some 1906 work of Whitehead:

Tuesday, September 24, 2019

Emissary

Filed under: General — Tags: , , — m759 @ 8:04 PM
 

Thursday, September 12, 2019

Tetrahedral Structures

Filed under: General — Tags:  —
m759 @ 8:11 PM 

In memory of a Church emissary  who reportedly died on  September 4 . . . .

Playing with shapes related to some 1906 work of Whitehead:

Saturday, September 21, 2019

Annals of Random Fandom

Filed under: General — Tags: , — m759 @ 5:46 PM

For Dan Brown fans …

… and, for fans of The Matrix, another tale
from the above death date: May 16, 2019 —

An illustration from the above
Miracle Octad Generator post:

Related mathematics — Tetrahedron vs. Square.

Saturday, September 14, 2019

The Inappropriate Capstone

Filed under: General — Tags: — m759 @ 4:59 AM

The All-Night Record Player

Filed under: General — Tags: — m759 @ 4:00 AM

See "Politics of Experience" and "Blue Guitar."

IMAGE- Scene from 'Oblivion' (2013) 

Friday, September 13, 2019

Schoolgirl Space…

Filed under: General — Tags: — m759 @ 4:56 AM

According to Wikipedia

See also Schoolgirl Space in this journal.

Thursday, September 12, 2019

Tetrahedral Structures

Filed under: General — Tags: — m759 @ 8:11 PM

In memory of a Church emissary who reportedly died on September 4,
here is a Log24 flashback reposted on that date —

Related poetry —

"To every man upon this earth,
Death cometh soon or late.
And how can man die better
Than facing fearful odds,
For the ashes of his fathers,
and the temples of his gods…?"

— Macaulay, quoted in the April 2013 film "Oblivion"

Related fiction —

Thursday, August 15, 2019

Schoolgirl Space — Tetrahedron or Square?

Filed under: General — Tags: , — m759 @ 9:03 PM

The exercise in the previous post  was suggested by a passage
purporting to "use standard block design theory" that was written
by some anonymous author at Wikipedia on March 1, 2019:

Here "rm OR" apparently means "remove original research."

Before the March 1 revision . . .

The "original research" objected to and removed was the paragraph
beginning "To explain this further."  That paragraph was put into the
article earlier on Feb. 28 by yet another anonymous author (not  by me).

An account of my own (1976 and later) original research on this subject 
is pictured below, in a note from Feb. 20, 1986 —

'The relativity problem in finite geometry,' 1986

On Steiner Quadruple Systems of Order 16

Filed under: General — Tags: , — m759 @ 4:11 AM

An image from a Log24 post of March 5, 2019

Cullinane's 1978  square model of PG(3,2)

The following paragraph from the above image remains unchanged
as of this morning at Wikipedia:

"A 3-(16,4,1) block design has 140 blocks of size 4 on 16 points,
such that each triplet of points is covered exactly once. Pick any
single point, take only the 35 blocks containing that point, and
delete that point. The 35 blocks of size 3 that remain comprise
a PG(3,2) on the 15 remaining points."

Exercise —

Prove or disprove the above assertion about a general "3-(16,4,1) 
block design," a structure also known as a Steiner quadruple system
(as I pointed out in the March 5 post).

Relevant literature —

A paper from Helsinki in 2005* says there are more than a million
3-(16,4,1) block designs, of which only one has an automorphism
group of order 322,560. This is the affine 4-space over GF(2),
from which PG(3,2) can be derived using the well-known process
from finite geometry described in the above Wikipedia paragraph.

* "The Steiner quadruple systems of order 16," by Kaski et al.,
   Journal of Combinatorial Theory Series A  
Volume 113, Issue 8, 
   November 2006, pages 1764-1770.

Saturday, August 10, 2019

Schoolgirl Space* Revisited:

Filed under: General — Tags: , — m759 @ 10:51 PM

The Square "Inscape" Model of
the Generalized Quadrangle W(2)

Click image to enlarge.

* The title refers to the role of PG (3,2) in Kirkman's schoolgirl problem.
For some backstory, see my post Anticommuting Dirac Matrices as Skew Lines
and, more generally, posts tagged Dirac and Geometry.

Wednesday, July 17, 2019

The Artsy Quantum Realm

Filed under: General — Tags: — m759 @ 6:38 PM
 

arXiv.org > quant-ph > arXiv:1905.06914 

Quantum Physics

Placing Kirkman's Schoolgirls and Quantum Spin Pairs on the Fano Plane: A Rainbow of Four Primary Colors, A Harmony of Fifteen Tones

J. P. Marceaux, A. R. P. Rau

(Submitted on 14 May 2019)

A recreational problem from nearly two centuries ago has featured prominently in recent times in the mathematics of designs, codes, and signal processing. The number 15 that is central to the problem coincidentally features in areas of physics, especially in today's field of quantum information, as the number of basic operators of two quantum spins ("qubits"). This affords a 1:1 correspondence that we exploit to use the well-known Pauli spin or Lie-Clifford algebra of those fifteen operators to provide specific constructions as posed in the recreational problem. An algorithm is set up that, working with four basic objects, generates alternative solutions or designs. The choice of four base colors or four basic chords can thus lead to color diagrams or acoustic patterns that correspond to realizations of each design. The Fano Plane of finite projective geometry involving seven points and lines and the tetrahedral three-dimensional simplex of 15 points are key objects that feature in this study.

Comments:16 pages, 10 figures

Subjects:Quantum Physics (quant-ph)

Cite as:arXiv:1905.06914 [quant-ph]

 (or arXiv:1905.06914v1 [quant-ph] for this version)

Submission history

From: A. R. P. Rau [view email] 
[v1] Tue, 14 May 2019 19:11:49 UTC (263 KB)

See also other posts tagged Tetrahedron vs. Square.

Life in Palermo

Filed under: General — Tags: — m759 @ 9:55 AM

See also other posts tagged Tetrahedron vs. Square, and a related
Log24 search for "Schoolgirl + Space."

Saturday, July 13, 2019

Live from New York, It’s …

Filed under: General — Tags: , , , — m759 @ 11:30 PM

Curse of the Fire Temple

"Power outages hit parts of Manhattan
plunging subways, Broadway, into darkness"

New York Post  this evening

Which Roof?

Filed under: General — Tags: , , — m759 @ 10:15 AM

Related material — Tetrahedron vs. Square and Cézanne's Greetings

Compare and contrast:

A figure from St. Patrick's Day 2004 that might represent a domed  roof

Inscribed Carpenter's Square:

In Latin, NORMA

and a cinematic "Fire Temple" from 2019

Friday, July 12, 2019

Holloway Today

Filed under: General — Tags: — m759 @ 8:23 AM

"The area is home to many artists and people who work in
 the media, including many journalists, writers and professionals 
working in film and television." — Wikipedia

Tusen takk to My Square Lady —

Tuesday, July 9, 2019

Perception of Space

Filed under: General — Tags: , — m759 @ 10:45 AM

(Continued)

The three previous posts have now been tagged . . .

Tetrahedron vs. Square  and  Triangle vs. Cube.

Related material —

Tetrahedron vs. Square:

Labeling the Tetrahedral Model  (Click to enlarge) —

Triangle vs. Cube:

and, from the date of the above John Baez remark —

Dreamtimes

Filed under: General — Tags: , — m759 @ 4:27 AM

“I am always the figure in someone else’s dream. I would really rather
sometimes make my own figures and make my own dreams.”

— John Malkovich at squarespace.com, January 10, 2017

Also on that date . . .

.

Monday, July 8, 2019

Exploring Schoolgirl Space

Filed under: General — Tags: , , , — m759 @ 9:48 AM

See also "Quantum Tesseract Theorem" and "The Crosswicks Curse."

Sunday, July 7, 2019

Schoolgirl Problem

Filed under: General — Tags: , — m759 @ 11:18 PM

Anonymous remarks on the schoolgirl problem at Wikipedia —

"This solution has a geometric interpretation in connection with 
Galois geometry and PG(3,2). Take a tetrahedron and label its
vertices as 0001, 0010, 0100 and 1000. Label its six edge centers
as the XOR of the vertices of that edge. Label the four face centers
as the XOR of the three vertices of that face, and the body center
gets the label 1111. Then the 35 triads of the XOR solution correspond
exactly to the 35 lines of PG(3,2). Each day corresponds to a spread
and each week to a packing
."

See also Polster + Tetrahedron in this  journal.

There is a different "geometric interpretation in connection with
Galois geometry and PG(3,2)" that uses a square  model rather
than a tetrahedral  model. The square  model of PG(3,2) last
appeared in the schoolgirl-problem article on Feb. 11, 2017, just
before a revision that removed it.

Saturday, December 17, 2016

Tetrahedral Death Star

Filed under: General,Geometry — Tags: , — m759 @ 10:00 PM

Continuing the "Memory, History, Geometry" theme
from yesterday

See Tetrahedral,  Oblivion,  and Tetrahedral Oblivion.

IMAGE- From 'Oblivion' (2013), the Mother Ship

"Welcome home, Jack."

Saturday, December 10, 2016

Folk Etymology

Images from Burkard Polster's Geometrical Picture Book

See as well in this journal the large  Desargues configuration, with
15 points and 20 lines instead of 10 points and 10 lines as above.

Exercise:  Can the large Desargues configuration be formed
by adding 5 points and 10 lines to the above Polster model
of the small configuration in such a way as to preserve
the small-configuration model's striking symmetry?  
(Note: The related figure below from May 21, 2014, is not
necessarily very helpful. Try the Wolfram Demonstrations
model
, which requires a free player download.)

Labeling the Tetrahedral Model (Click to enlarge) —

Related folk etymology (see point a  above) —

Related literature —

The concept  of "fire in the center" at The New Yorker , 
issue dated December 12, 2016, on pages 38-39 in the
poem by Marsha de la O titled "A Natural History of Light."

Cézanne's Greetings.

Thursday, September 15, 2016

The Smallest Perfect Number/Universe

Filed under: General,Geometry — Tags: , , — m759 @ 6:29 AM

The smallest perfect number,* six, meets
"the smallest perfect universe,"** PG(3,2).

IMAGE- Geometry of the Six-Set, Steven H. Cullinane, April 23, 2013

  * For the definition of "perfect number," see any introductory
    number-theory text that deals with the history of the subject.
** The phrase "smallest perfect universe" as a name for PG(3,2),
     the projective 3-space over the 2-element Galois field GF(2),
     was coined by math writer Burkard Polster. Cullinane's square
     model of PG(3,2) differs from the earlier tetrahedral model
     discussed by Polster.

Sunday, August 11, 2013

Demonstrations

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

IMAGE- Wolfram Demonstrations, '15 Point Projective Space'

IMAGE- From 'Oblivion' (2013), the Mother Ship

"Welcome home, Jack."

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