Log24

Friday, October 13, 2023

Lightbox for a Friday the 13th

Filed under: General — Tags: — m759 @ 12:35 pm

For a different sort of Lightbox, more closely associated with
the number 13, see instances in this journal of . . .

IMAGE- The 13 symmetry axes of the cube

(Adapted from Encyclopaedia Britannica,
Eleventh Edition (1911), Crystallography .)

"Before time began . . . ." — Optimus Prime

Wednesday, January 13, 2021

Working Backwards: 13 in the 11th

Filed under: General — m759 @ 12:37 am

IMAGE- The 13 symmetry axes of the cube

(Adapted from Encyclopaedia Britannica,
Eleventh Edition (1911), Crystallography .)

Monday, April 13, 2020

Cubes and Axes

Filed under: General — Tags: — m759 @ 12:55 pm

See also this  journal on November 29, 2011 —The Flight from Ennui.

Related illustration from earlier in 2011 —

See also this  journal on 20 Sept. 2011 — Relativity Problem Revisited —
as well as Congregated Light.

Friday, December 13, 2019

Apollo’s 13 Revisited

Filed under: General — Tags: — m759 @ 12:59 am

IMAGE- The 13 symmetry axes of the cube

(Adapted from Encyclopaedia Britannica,
 Eleventh Edition (1911), Crystallography .)

Monday, May 19, 2014

Un-Rubik Cube

Filed under: General,Geometry — m759 @ 10:48 am

IMAGE- Britannica 11th edition on the symmetry axes and planes of the cube

See also Cube Symmetry Planes  in this journal.

Friday, May 13, 2011

Apollo’s 13

Filed under: General,Geometry — Tags: — m759 @ 6:36 am

Continued … See related previous posts.

IMAGE- The 13 symmetry axes of the cube

Those who prefer narrative to mathematics
may consult Wikipedia on The Cosmic Cube.

Wednesday, September 13, 2023

Edgelord School

Filed under: General — Tags: , , , , , — m759 @ 9:20 am
 

Monday, May 8, 2017

New Pinterest Board

Filed under: Uncategorized — m759 @ 9:29 PM 

https://www.pinterest.com/stevenhcullinane/art-space/

The face at lower left above is that of an early Design edgelord.

A product of that edgelord's school

See a design by Prince-Ramus in today's New York Times —

Remarks quoted here  on the above San Diego date —

A related void —

IMAGE- The 13 symmetry axes of the cube

Sunday, July 2, 2023

Badlands Philosophy

Filed under: General — Tags: — m759 @ 12:29 pm

This afternoon's Windows lockscreen is Badlands National Park —

From this morning's post, a phrase from Schopenhauer

"Apparent Design in the Fate of the Individual."

An apparent design in the philosophy of Optimus Prime —

"Before time began, there was the Cube" —

IMAGE- The 13 symmetry axes of the cube

Click the image for further remarks.

Monday, June 27, 2022

Dealing With Cubism

Filed under: General — Tags: , , — m759 @ 7:59 pm

Continued from April 12, 2022.

"It’s important, as art historian Reinhard Spieler has noted,
that after a brief, unproductive stay in Paris, circa 1907,
Kandinsky chose to paint in Munich. That’s where he formed
the Expressionist art group Der Blaue Reiter  (The Blue Rider) —
and where he avoided having to deal with cubism."

— David Carrier, 

Remarks by Louis Menand in The New Yorker  today —

"The art world isn’t a fixed entity.
It’s continually being reconstituted
as new artistic styles emerge." 

IMAGE- The 13 symmetry axes of the cube

(Adapted from Encyclopaedia Britannica,
Eleventh Edition (1911), Crystallography .)

"Before time began, there was the Cube."
— Optimus Prime

See as well Verbum  (February 18, 2017).

Related dramatic music

"Westworld Season 4 begins at Hoover Dam,
with William looking to buy the famous landmark.
What does he consider to be 'stolen' data that is inside?" 

Saturday, March 26, 2022

Box Geometry: Space, Group, Art  (Work in Progress)

Filed under: General — Tags: — m759 @ 2:06 am

Many structures of finite geometry can be modeled by
rectangular or cubical arrays ("boxes") —
of subsquares or subcubes (also "boxes").

Here is a draft for a table of related material, arranged
as internet URL labels.

Finite Geometry Notes — Summary Chart
 

Name Tag .Space .Group .Art
Box4

2×2 square representing the four-point finite affine geometry AG(2,2).

(Box4.space)

S4 = AGL(2,2)

(Box4.group)

 

(Box4.art)

Box6 3×2 (3-row, 2-column) rectangular array
representing the elements of an arbitrary 6-set.
S6  
Box8 2x2x2 cube or  4×2 (4-row, 2-column) array. S8 or Aor  AGL(3,2) of order 1344, or  GL(3,2) of order 168  
Box9 The 3×3 square. AGL(2,3) or  GL(2,3)  
Box12 The 12 edges of a cube, or  a 4×3  array for picturing the actions of the Mathieu group M12. Symmetries of the cube or  elements of the group M12  
Box13 The 13 symmetry axes of the cube. Symmetries of the cube.  
Box15 The 15 points of PG(3,2), the projective geometry
of 3 dimensions over the 2-element Galois field.
Collineations of PG(3,2)  
Box16 The 16 points of AG(4,2), the affine geometry
of 4 dimensions over the 2-element Galois field.

AGL(4,2), the affine group of 
322,560 permutations of the parts
of a 4×4 array (a Galois tesseract)

 
Box20 The configuration representing Desargues's theorem.    
Box21 The 21 points and 21 lines of PG(2,4).    
Box24 The 24 points of the Steiner system S(5, 8, 24).    
Box25 A 5×5 array representing PG(2,5).    
Box27 The 3-dimensional Galois affine space over the
3-element Galois field GF(3).
   
Box28 The 28 bitangents of a plane quartic curve.    
Box32 Pair of 4×4 arrays representing orthogonal 
Latin squares.
Used to represent
elements of AGL(4,2)
 
Box35 A 5-row-by-7-column array representing the 35
lines in the finite projective space PG(3,2)
PGL(3,2), order 20,160  
Box36 Eurler's 36-officer problem.    
Box45 The 45 Pascal points of the Pascal configuration.    
Box48 The 48 elements of the group  AGL(2,3). AGL(2,3).  
Box56

The 56 three-sets within an 8-set or
56 triangles in a model of Klein's quartic surface or
the 56 spreads in PG(3,2).

   
Box60 The Klein configuration.    
Box64 Solomon's cube.    

— Steven H. Cullinane, March 26-27, 2022

Sunday, March 13, 2022

Google News Spotlight

Filed under: General — m759 @ 5:44 pm

Before time began . . .

IMAGE- Massimo Vignelli, his wife Lella, and cube

Friday, December 31, 2021

Aesthetics in Academia

Filed under: General — Tags: — m759 @ 9:33 am

Related art — The non-Rubik 3x3x3 cube —

The above structure illustrates the affine space of three dimensions
over the three-element finite (i.e., Galois) field, GF(3). Enthusiasts
of Judith Brown's nihilistic philosophy may note the "radiance" of the
13 axes of symmetry within the "central, structuring" subcube.

I prefer the radiance  (in the sense of Aquinas) of the central, structuring 
eightfold cube at the center of the affine space of six dimensions over
the two-element field GF(2).

Friday, October 13, 2017

Speak, Memra

Filed under: General,Geometry — Tags: — m759 @ 11:59 am

The above was suggested by a Log24 review of October 13, 2002,
which in turn suggested a Log24 search for Carousel that yielded
(from Bloomsday Lottery) —

See as well Asimov's "prime radiant," and an illustration
of the number 13 as a radiant prime

"The Prime Radiant can be adjusted to your mind,
and all corrections and additions can be made
through mental rapport. There will be nothing to
indicate that the correction or addition is yours.
In all the history of the Plan there has been no
personalization. It is rather a creation of all of us 
together. Do you understand?"  

"Yes, Speaker!"

— Isaac Asimov, 
    Second Foundation , Ch. 8: Seldon's Plan

"Before time began, there was the Cube."
— Optimus Prime

See also Transformers in this journal.

Tuesday, June 20, 2017

All-Spark Notes

Filed under: General,Geometry — Tags: — m759 @ 1:55 pm

(Continued)

"For years, the AllSpark rested, sitting dormant
like a giant, useless art installation."

— Vinnie Mancuso at Collider.com yesterday

Related material —

Dormant cube

IMAGE- Britannica 11th edition on the symmetry axes and planes of the cube

Giant, useless art installation —

Sol LeWitt at MASS MoCA.  See also LeWitt in this journal.

Monday, April 3, 2017

Odd Core

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

 

3x3x3 Galois cube, gray and white

Sunday, January 1, 2017

Like the Horizon

(Continued from a remark by art critic Peter Schjeldahl quoted here
last  year on New Year's Day in the post "Art as Religion.")

"The unhurried curve got me.
It was like the horizon of a world
that made a non-world of
all of the space outside it."

— Peter Schjeldahl, "Postscript: Ellsworth Kelly,"
The New Yorker , December 30, 2015

This suggests some further material from the paper
that was quoted here yesterday on New Year's Eve —

"In teaching a course on combinatorics I have found
students doubting the existence of a finite projective
plane geometry with thirteen points on the grounds
that they could not draw it (with 'straight' lines)
on paper although they had tried to do so. Such a
lack of appreciation of the spirit of the subject is but
a consequence of the elements of formal geometry
no longer being taught in undergraduate courses.
Yet these students were demanding the best proof of
existence, namely, production of the object described."

— Derrick Breach (See his obituary from 1996.)

A related illustration of the 13-point projective plane
from the University of Western Australia:

Projective plane of order 3

(The four points on the curve
at the right of the image are
the points on the line at infinity .)

The above image is from a post of August 7, 2012,
"The Space of Horizons."  A related image —

Click on the above image for further remarks.

Saturday, September 17, 2016

Interior/Exterior

Filed under: General,Geometry — m759 @ 12:25 am


3x3x3 Galois cube, gray and white

Friday, September 2, 2016

Raiders of the Lost Birthday

Filed under: General — Tags: , , — m759 @ 10:00 am

Some images from the posts of last July 13
(Harrison Ford's birthday) may serve as funeral
ornaments for the late Prof. David Lavery.

IMAGE- Massimo Vignelli, his wife Lella, and cube

Magic cube and corresponding hexagram, or Star of David, with faces mapped to lines and edges mapped to points

See as well posts on "Silent Snow" and "Starlight Like Intuition."

Saturday, October 10, 2015

Epiphany in Paris

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

It's 10 PM …

    

Related material: Adam Gopnik, The King in the Window.

Wednesday, May 13, 2015

Space

Filed under: General,Geometry — Tags: , — m759 @ 2:00 pm

Notes on space for day 13 of May, 2015 —

The 13 symmetry axes of the cube may be viewed as
the 13 points of the Galois projective space PG(2,3).
This space (a plane) may also be viewed as the nine points
of the Galois affine space AG(2,3) plus the four points on
an added "line at infinity."

Related poetic material:

The ninefold square and Apollo, as well as 

http://www.log24.com/log/pix11A/110426-ApolloAndDionysus.jpg

Thursday, December 18, 2014

Platonic Analogy

Filed under: General,Geometry — Tags: , , — m759 @ 2:23 pm

(Five by Five continued)

As the 3×3 grid underlies the order-3 finite projective plane,
whose 13 points may be modeled by
the 13 symmetry axes of the cube,
so the 5×5 grid underlies the order-5 finite projective plane,
whose 31 points may be modeled by
the 31 symmetry axes of the dodecahedron.

See posts tagged Galois-Plane Models.

Wednesday, November 26, 2014

Class Act

Filed under: General,Geometry — Tags: , — m759 @ 7:18 am

Update of Nov. 30, 2014 —

For further information on the geometry in
the remarks by Eberhart below, see
pp. 16-17 of A Geometrical Picture Book ,
by Burkard Polster (Springer, 1998). Polster
cites a different article by Lemay.

A search for background to the exercise in the previous post
yields a passage from the late Stephen Eberhart:

The first three primes p = 2, 3, and 5 therefore yield finite projective planes with 7, 13, and 31 points and lines, respectively. But these are just the numbers of symmetry axes of the five regular solids, as described in Plato's Timaeus : The tetrahedron has 4 pairs of face planes and corner points + 3 pairs of opposite edges, totalling 7 axes; the cube has 3 pairs of faces + 6 pairs of edges + 4 pairs of corners, totalling 13 axes (the octahedron simply interchanges the roles of faces and corners); and the pentagon dodecahedron has 6 pairs of faces + 15 pairs of edges + 10 pairs of corners, totalling 31 axes (the icosahedron again interchanging roles of faces and corners). This is such a suggestive result, one would expect to find it dealt with in most texts on related subjects; instead, while "well known to those who well know such things" (as Richard Guy likes to quip), it is scarcely to be found in the formal literature [9]. The reason for the common numbers, it turns out, is that the groups of symmetry motions of the regular solids are subgroups of the groups of collineations of the respective finite planes, a face axis being different from an edge axis of a regular solid but all points of a projective plane being alike, so the latter has more symmetries than the former.

[9] I am aware only of a series of in-house publications by Fernand Lemay of the Laboratoire de Didactique, Faculté des Sciences de I 'Éducation, Univ. Laval, Québec, in particular those collectively titled Genèse de la géométrie  I-X.

— Stephen Eberhart, Dept. of Mathematics,
California State University, Northridge, 
"Pythagorean and Platonic Bridges between
Geometry and Algebra," in BRIDGES: Mathematical
Connections in Art, Music, and Science 
, 1998,
archive.bridgesmathart.org/1998/bridges1998-121.pdf

Eberhart died of bone cancer in 2003. A memorial by his
high school class includes an Aug. 7, 2003, transcribed
letter from Eberhart to a classmate that ends…


… I earned MA’s in math (UW, Seattle) and history (UM, Missoula) where a math/history PhD program had been announced but canceled.  So 1984 to 2002 I taught math (esp. non-Euclidean geometry) at C.S.U. Northridge.  It’s been a rich life.  I’m grateful. 
 
Steve
 

See also another informative BRIDGES paper by Eberhart
on mathematics and the seven traditional liberal arts.

Tuesday, November 25, 2014

Euclidean-Galois Interplay

Filed under: General,Geometry — Tags: , , — m759 @ 11:00 am

For previous remarks on this topic, as it relates to
symmetry axes of the cube, see previous posts tagged Interplay.

The above posts discuss, among other things, the Galois
projective plane of order 3, with 13 points and 13 lines.

Oxley's 2004 drawing of the 13-point projective plane

These Galois points and lines may be modeled in Euclidean geometry
by the 13 symmetry axes and the 13 rotation planes
of the Euclidean cube. They may also be modeled in Galois geometry
by subsets of the 3x3x3 Galois cube (vector 3-space over GF(3)).

http://www.log24.com/log/pix11A/110427-Cube27.jpg

   The 3×3×3 Galois Cube 

Exercise: Is there any such analogy between the 31 points of the
order-5 Galois projective plane and the 31 symmetry axes of the
Euclidean dodecahedron and icosahedron? Also, how may the
31 projective points  be naturally pictured as lines  within the 
5x5x5 Galois cube (vector 3-space over GF(5))?

Update of Nov. 30, 2014 —

For background to the above exercise, see
pp. 16-17 of A Geometrical Picture Book ,
by Burkard Polster (Springer, 1998), esp.
the citation to a 1983 article by Lemay.

Thursday, November 13, 2014

Mort de Grothendieck

Filed under: General — m759 @ 5:55 pm

Alexandre Grothendieck est mort jeudi matin
à l’hôpital de Saint-Girons (Ariège), à l’âge de 86 ans.”

Update of 6: 16 PM ET:  A memorial of sorts, from May 27 this year:

IMAGE- Massimo Vignelli, his wife Lella, and cube

Monday, January 13, 2014

A Prime for Marissa

Filed under: General,Geometry — m759 @ 10:00 pm

"I don't like odd numbers, and I really don't like primes."

Marissa Mayer

See Cube Symmetry Axes in this journal.

IMAGE- The 13 symmetry axes of the cube

Saturday, April 13, 2013

Narrative

Filed under: General — m759 @ 6:16 pm

Two friends from Brooklyn —

"… both marveled at early Ingmar Bergman movies."

One of the friends' "humor was inspired by
surrealist painters and Franz Kafka."

Wikipedia

"Most of Marvel's fictional characters operate in
a single reality known as the Marvel Universe…."

This journal yesterday

    

Related material:  The Cosmic Cube.

Friday, April 12, 2013

Midnight in Paris

Filed under: General,Geometry — m759 @ 6:00 pm

Surreal requiem for the late Jonathan Winters:

"They 'burn, burn, burn like fabulous yellow roman candles
exploding like spiders across the stars,'
as Jack Kerouac once wrote. It was such a powerful
image that Wal-Mart sells it as a jigsaw puzzle."

— "When the Village Was the Vanguard,"
       by Henry Allen, in today's Wall Street Journal

See also Damnation Morning and the picture in
yesterday evening's remarks on art:

    

Thursday, April 11, 2013

Naked Art

Filed under: General,Geometry — m759 @ 9:48 pm

The New Yorker  on Cubism:

"The style wasn’t new, exactly— or even really a style,
in its purest instances— though it would spawn no end
of novelties in art and design. Rather, it stripped naked
certain characteristics of all pictures. Looking at a Cubist
work, you are forced to see how you see. This may be
gruelling, a gymnasium workout for eye and mind.
It pays off in sophistication."

Online "Culture Desk" weblog, posted today by Peter Schjeldahl

Non-style from 1911:

IMAGE- Britannica 11th edition on the symmetry axes and planes of the cube

See also Cube Symmetry Planes  in this  journal.

A comment at The New Yorker  related to Schjeldahl's phrase "stripped naked"—

"Conceptualism is the least seductive modern-art movement."

POSTED 4/11/2013, 3:54:37 PM BY CHRISKELLEY

(The "conceptualism" link was added to the quoted comment.)

Tuesday, February 19, 2013

Configurations

Filed under: General,Geometry — Tags: , , — m759 @ 12:24 pm

Yesterday's post Permanence dealt with the cube
as a symmetric model of the finite projective plane
PG(2,3), which has 13 points and 13 lines. The points
and lines of the finite geometry occur in the cube as
the 13 axes of symmetry and the 13 planes through
the center perpendicular to those axes. If the three
axes lying in  a plane that cuts the cube in a hexagon
are supplemented by the axis perpendicular  to that
plane, each plane is associated with four axes and,
dually, each axis is associated with four planes.

My web page on this topic, Cubist Geometries, was
written on February 27, 2010, and first saved to the
Internet Archive on Oct. 4, 2010

For a more recent treatment of this topic that makes
exactly the same points as the 2010 page, see p. 218
of Configurations from a Graphical Viewpoint , by
Tomaž Pisanski and Brigitte Servatius, published by
Springer on Sept. 23, 2012 (date from both Google
Books
and Amazon.com):

For a similar 1998 treatment of the topic, see Burkard Polster's 
A Geometrical Picture Book  (Springer, 1998), pp. 103-104.

The Pisanski-Servatius book reinforces my argument of Jan. 13, 2013,
that the 13 planes through the cube's center that are perpendicular
to the 13 axes of symmetry of the cube should be called the cube's 
symmetry planes , contradicting the usual use of of that term.

That argument concerns the interplay  between Euclidean and
Galois geometry. Pisanski and Servatius (and, in 1998, Polster)
emphasize the Euclidean square and cube as guides* to
describing the structure of a Galois space. My Jan. 13 argument
uses Galois  structures as a guide to re-describing those of Euclid .
(For a similar strategy at a much more sophisticated level,
see a recent Harvard Math Table.)

Related material:  Remarks on configurations in this journal
during the month that saw publication of the Pisanski-Servatius book.

* Earlier guides: the diamond theorem (1978), similar theorems for
  2x2x2 (1984) and 4x4x4 cubes (1983), and Visualizing GL(2,p)
  (1985). See also Spaces as Hypercubes (2012).

Saturday, January 14, 2012

Defining Form (continued)

Filed under: General,Geometry — Tags: , — m759 @ 12:00 pm

Detail of Sylvie Donmoyer picture discussed
here on January 10

http://www.log24.com/log/pix12/120114-Donmoyer-Still-Life-CubeDetail.jpg

The "13" tile may refer to the 13 symmetry axes
in the 3x3x3 Galois cube, or the corresponding
13 planes through the center in that cube. (See
this morning's post and Cubist Geometries.)

Wednesday, August 31, 2011

Odin’s Day

Filed under: General — m759 @ 12:00 pm

Today is Wednesday.

O.E. Wodnesdæg  "Woden's day," a Gmc. loan-translation of L. dies Mercurii  "day of Mercury" (cf. O.N. Oðinsdagr , Swed. Onsdag , O.Fris. Wonsdei , M.Du. Wudensdach ). For Woden , see Odin  . — Online Etymology Dictionary

http://www.log24.com/log/pix11B/110831-HopkinsAsOdin.jpg

Above: Anthony Hopkins as Odin in the 2011 film "Thor"

Hugo Weaving as Johann Schmidt in the related 2011 film "Captain America"—

"The Tesseract* was the jewel of Odin's treasure room."

http://www.log24.com/log/pix11B/110831-JohannSchmidt.jpg

Weaving also played Agent Smith in The Matrix Trilogy.

The figure at the top in the circle of 13** "Thor" characters above is Agent Coulson.

"I think I'm lucky that they found out they need somebody who's connected to the real world to help bring these characters all together."

— Clark Gregg, who plays Agent Coulson in "Thor," at UGO.com

For another circle of 13, see the Crystal Skull film implicitly referenced in the Bright Star link from Abel Prize (Friday, Aug. 26, 2011)—

http://www.log24.com/log/pix11B/110831-BrightStar.jpg

Today's New York Times  has a quote about a former mathematician who died on that day (Friday, Aug. 26, 2011)—

"He treated it like a puzzle."

Sometimes that's the best you can do.

* See also tesseract  in this journal.

** For a different arrangement of 13 things, see the cube's 13 axes in this journal.

Monday, December 13, 2010

Mathematics and Narrative continued…

Filed under: General,Geometry — m759 @ 7:20 am

Apollo's 13: A Group Theory Narrative —

I. At Wikipedia —

http://www.log24.com/log/pix10B/101213-GroupTheory.jpg

II. Here —

See Cube Spaces and Cubist Geometries.

The 13 symmetry axes of the (Euclidean) cube–
exactly one axis for each pair of opposite
subcubes in the 27-part (Galois) 3×3×3 cube–

The 13 symmetry axes of the cube

A note from 1985 describing group actions on a 3×3 plane array—

http://www.log24.com/log/pix10A/100621-VisualizingDetail.gif

Undated software by Ed Pegg Jr. displays
group actions on a 3×3×3 cube that extend the
3×3 group actions from 1985 described above—

Ed Pegg Jr.'s program at Wolfram demonstrating concepts of a 1985<br />
note by Cullinane

Pegg gives no reference to the 1985 work on group actions.

Monday, June 28, 2010

Shall I Compare Thee

Filed under: General,Geometry — Tags: , — m759 @ 11:02 am

Margaret Soltan on a summer's-day poem by D.A. Powell

first, a congregated light, the brilliance of a meadowland in bloom
and then the image must fail, as we must fail, as we

graceless creatures that we are, unmake and befoul our beds
don’t tell me deluge.     don’t tell me heat, too damned much heat

"Specifically, your trope is the trope of every life:
 the organizing of the disparate parts of a personality
 into a self (a congregated light), blazing youth
 (a meadowland in bloom), and then the failure
 of that image, the failure of that self to sustain itself."

Alternate title for Soltan's commentary, suggested by yesterday's Portrait:

Smart Jewish Girl Fwows Up.

Midrash on Soltan—

Congregated Light

The 13 symmetry axes 
of the cube

Meadowland

Appalachian meadow

Failure

Wert thou my enemy, O thou my friend,
How wouldst thou worse, I wonder, than thou dost
Defeat, thwart me?

Coda

"…meadow-down is not distressed
For a rainbow footing…."

Sunday, June 27, 2010

Sunday at the Apollo

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

27

 

The 13 symmetry axes of the (Euclidean) cube–
exactly one axis for each pair of opposite
  subcubes in the 27-part (Galois) 3×3×3 cube–

The 13 symmetry axes of the cube

Saturday, March 13, 2010

Space Cowboy

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

From yesterday's Seattle Times

According to police, employees of a Second Avenue mission said the suspect, clad in black and covered in duct tape, had come into the mission "and threatened to blow the place up." He then told staffers "that he was a vampire and wanted to eat people."

The man… also called himself "a space cowboy"….

This suggests two film titles…

Plan 9 from Outer Space

Rebecca Goldstein and a Cullinane quaternion

and Apollo's 13

The 13 symmetry axes of the (Euclidean) cube–
exactly one axis for each pair of opposite
  subcubes in the (Galois) 3×3×3 cube–

The 13 symmetry axes of the cube

Saturday, February 27, 2010

Cubist Geometries

Filed under: General,Geometry — Tags: , , — m759 @ 2:01 pm

"The cube has…13 axes of symmetry:
  6 C2 (axes joining midpoints of opposite edges),
4 C3 (space diagonals), and
3C4 (axes joining opposite face centroids)."
–Wolfram MathWorld article on the cube

These 13 symmetry axes can be used to illustrate the interplay between Euclidean and Galois geometry in a cubic model of the 13-point Galois plane.

The geometer's 3×3×3 cube–
27 separate subcubes unconnected
by any Rubik-like mechanism–

The 3x3x3 geometer's cube, with coordinates

The 13 symmetry axes of the (Euclidean) cube–
exactly one axis for each pair of opposite
  subcubes in the (Galois) 3×3×3 cube–

The 13 symmetry axes of the cube

A closely related structure–
the finite projective plane
with 13 points and 13 lines–

Oxley's 2004 drawing of the 13-point projective plane

A later version of the 13-point plane
by Ed Pegg Jr.–

Ed Pegg Jr.'s 2007 drawing of the 13-point projective plane

A group action on the 3×3×3 cube
as illustrated by a Wolfram program
by Ed Pegg Jr. (undated, but closely
related to a March 26, 1985 note
by Steven H. Cullinane)–

Ed Pegg Jr.'s program at Wolfram demonstrating concepts of a 1985 note by Cullinane

The above images tell a story of sorts.
The moral of the story–

Galois projective geometries can be viewed
in the context of the larger affine geometries
from which they are derived.

The standard definition of points in a Galois projective plane is that they are lines through the (arbitrarily chosen) origin in a corresponding affine 3-space converted to a vector 3-space.

If we choose the origin as the center cube in coordinatizing the 3×3×3 cube (See Weyl's relativity problem ), then the cube's 13 axes of symmetry can, if the other 26 cubes have properly (Weyl's "objectively") chosen coordinates, illustrate nicely the 13 projective points derived from the 27 affine points in the cube model.

The 13 lines of the resulting Galois projective plane may be derived from Euclidean planes  through the cube's center point that are perpendicular to the cube's 13 Euclidean symmetry axes.

The above standard definition of points in a Galois projective plane may of course also be used in a simpler structure– the eightfold cube.

(The eightfold cube also allows a less standard way to picture projective points that is related to the symmetries of "diamond" patterns formed by group actions on graphic designs.)

See also Ed Pegg Jr. on finite geometry on May 30, 2006
at the Mathematical Association of America.

Sunday, January 24, 2010

Today’s Sermon

Filed under: General,Geometry — Tags: , — m759 @ 11:00 am

More Than Matter

Wheel in Webster’s Revised Unabridged Dictionary, 1913

(f) Poetry

The burden or refrain of a song.

⇒ “This meaning has a low degree of authority, but is supposed from the context in the few cases where the word is found.” Nares.

You must sing a-down a-down, An you call him a-down-a. O, how the wheel becomes it! Shak.

“In one or other of G. F. H. Shadbold’s two published notebooks, Beyond Narcissus and Reticences of Thersites, a short entry appears as to the likelihood of Ophelia’s enigmatic cry: ‘Oh, how the wheel becomes it!’ referring to the chorus or burden ‘a-down, a-down’ in the ballad quoted by her a moment before, the aptness she sees in the refrain.”

— First words of Anthony Powell’s novel “O, How the Wheel Becomes It!” (See Library Thing.)

Anthony Powell's 'O, How the Wheel Becomes It!' along with Laertes' comment 'This nothing's more than matter.'

Related material:

Photo uploaded on January 14, 2009
with caption “This nothing’s more than matter”

and the following nothings from this journal
on the same date– Jan. 14, 2009

The Fritz Leiber 'Spider' symbol in a square

A Singer 7-cycle in the Galois field with eight elements

The Eightfold (2x2x2) Cube

The Jewel in Venn's Lotus (photo by Gerry Gantt)

Powered by WordPress