Earlier in this journal, a more abstract approach . . .
Tuesday, March 4, 2025
Brick-Space News
Thursday, February 20, 2025
Coloring the Klein Correspondence
A Google search for "four color decomposition" yields an AI Overview —
My "four-color decomposition" theorem supplies some background
for last New Year's Eve's post on the Klein Correspondence.
Monday, February 10, 2025
Brick Space: Points with Parts
This post's "Points with Parts" title may serve as an introduction to
what has been called "the most powerful diagram in mathematics" —
the "Miracle Octad Generator" (MOG) of Robert T. Curtis.
Curtis himself has apparently not written on the geometric background
of his diagram — the finite projective spaces PG(5,2) and PG(3,2), of
five and of three dimensions over the two-element Galois field GF(2).
The component parts of the MOG diagram, the 2×4 Curtis "bricks,"
may be regarded* as forming both PG(5,2) and PG(3,2) . . .
Pace Euclid, points with parts. For more on the MOG's geometric
background, see the Klein correspondence in the previous post.
For a simpler example of "points with parts, see
http://m759.net/wordpress/?s=200229.
* Use the notions of Galois (XOR, or "symmetric-difference") addition
of even subsets, and such addition "modulo complementation," to
decrease the number of dimensions of the spaces involved.
Sunday, February 9, 2025
An AI Overview of Klein Quadric and MOG
See also a more accurate AI report from January 9, 2025 —
Grok 2 on the MOG and the Klein Correspondence:
HTML version, with corrections, of the above 9 January Grok 2 report —
|
Grok 2: Klein Correspondence and MOG, 9 Jan. 2025 . . . The Klein correspondence is closely related to the Miracle Octad Generator (MOG) through the mathematical structure they both engage with, particularly in the context of finite geometry and combinatorics.
Klein Correspondence: This refers to a mathematical framework that establishes a correspondence between Miracle Octad Generator (MOG): Introduced by R.T. Curtis, the MOG is a tool used in the study of the Mathieu group M24, the binary Golay code, and related structures like the Steiner system S(5,8,24). It consists of a 4×6 array where the positions are used to construct octads (sets of 8 elements) from given sets of 5 elements, reflecting the structure of the Steiner system. Relation Between Klein Correspondence and MOG:
Thus, the Klein correspondence serves as a foundational link that allows the MOG to operate by translating combinatorial problems into geometric ones, facilitating the study of complex mathematical structures like the Mathieu groups and Steiner systems. * Correction: Should be "a correspondence between points in a five-dimensional projective space and lines in a three-dimensional projective space." |
Update of ca. 9 AM ET Monday, Feb. 10, 2024 —
Neither AI report above mentions the Cullinane model of the five-
dimensional projective space PG(5,2) as a brick space — a space
whose points are the 2×4 bricks used in thte MOG. This is
understandable, as the notion of using bricks to model both PG(5,2)
and PG(3,2) has appeared so far only in this journal. See an
illustration from New Year's Eve . . . Dec. 31, 2024 —

Tuesday, January 14, 2025
Proofs
A phrase by Aitchison at Hiroshima . . .
"The proof of the above is a relabelling of the Klein quartic . . . ."
Related art — A relabelling of the Klein quadric by Curtis bricks:
Update of 12:26 PM EST Wednesday, January 15, 2025 —
Here is a large (17.5 MB) PDF file containing all posts touching upon
the concept underlying the above illustration — the Klein correspondence.
(A PDF reader such as Foxit is recommended for such large files.)
Saturday, January 11, 2025
Octads within a PG(5,2) Addition Table
Thursday, January 9, 2025
Grok 2 on the MOG and the Klein Correspondence
Related illustration —
|
— Transcription —
Grok 2 on Klein correspondence and MOG — 9 Jan. 2025 Prompt: How is the Klein correspondence related to the Miracle Octad Generator? Grok 2 response (with citations and links removed): The Klein correspondence is closely related to the Miracle Octad Generator (MOG) through the mathematical structure they both engage with, particularly in the context of finite geometry and combinatorics. Klein Correspondence: This refers to a mathematical framework that establishes a correspondence between points and lines in a projective space. Specifically, in the context of the MOG, it relates to the geometry of PG(3,2), the three-dimensional projective space over the field with two elements. The Klein correspondence, in this context, essentially connects the combinatorial aspects of partitions of an 8-set to the geometric structure of lines in PG(3,2). Miracle Octad Generator (MOG): Introduced by R.T. Curtis, the MOG is a tool used in the study of the Mathieu group M24, the binary Golay code, and related structures like the Steiner system S(5,8,24). It consists of a 4×6 array where the positions are used to construct octads (sets of 8 elements) from given sets of 5 elements, reflecting the structure of the Steiner system. Relation Between Klein Correspondence and MOG: Combinatorial and Geometric Link: The MOG uses the Klein correspondence to map partitions of an 8-set (into two 4-sets) to 4 parallel affine planes within PG(3,2). This mapping is natural and symmetrical, which is crucial for the MOG's functionality. The 35 partitions of an 8-set correspond to the 35 lines in PG(3,2), and this correspondence helps in understanding how to generate and visualize octads within the MOG framework. Structural Insight: The Klein correspondence provides a way to see how the MOG's method of generating octads can be understood geometrically. This insight is vital for exploring the symmetry and subgroup structure of M24, as the MOG's layout preserves these symmetries. Thus, the Klein correspondence serves as a foundational link that allows the MOG to operate by translating combinatorial problems into geometric ones, facilitating the study of complex mathematical structures like the Mathieu groups and Steiner systems. |
Sunday, January 5, 2025
Saturday, January 4, 2025
For a Contemporary Faustus
A contemporary minimalist composer whose work resembles that of
Thomas Mann's Doctor Faustus reportedly died at 85 Tuesday
in Paris on New Year's Eve (December 31, 2024). The phrase
"mathematical clarity" in his obituary in today's New York Times
suggests a synchronology check —
Compare and contrast.
Tuesday, December 31, 2024
The Yellow Brick Road to the
Miracle Octad Generator, with Conwell’s Heptads
The Klein quadric as background for the Miracle Octad Generator of R. T. Curtis —
See also Saniga on heptads in this journal.

Miracle Octad Generator, with Conwell’s Heptads
Monday, December 23, 2024
A Projective-Space Home for the Miracle Octad Generator
The natural geometric setting for the "bricks" in the Miracle Octad Generator
(MOG) of Robert T. Curtis is PG(5,2), the projective 5-space over GF(2).
The Klein correspondence mirrors the 35 lines of PG(3,2) — and hence, via the
graphic approach below, the 35 "heavy bricks" of the MOG that match those
lines — in PG(5,2), where the bricks may be studied with geometric methods,
as an alternative to Curtis's original MOG combinatorial construction methods.
The construction below of a PG(5,2) brick space is analogous to the
"line diagrams" construction of a PG(3,2) in Cullinane's diamond theorem.

Saturday, December 21, 2024
Coordinatizing Brick Space
Exercise: The eight-part diagrams in the graphic "brick space"
model of PG(5,2) below need to be suitably labeled with six-part
GF(2) coordinates to help illustrate the Klein correspondence that
underlies the large Mathieu group M24.
A possible approach: The lines separating dark squares from light
(i.e., blue from white or yellow) in the figure above may be added
in XOR fashion (as if they were diamond theorem line diagrams)
to form a six dimensional vector space, which, after a suitable basis
is chosen, may be represented by six-tuples of 0's and 1's.
Related reading —
log24.com/log24/241221-'Brick Space « Log24' – m759.net.pdf .
This is a large (15.1 MB) file. The Foxit PDF reader is recommended.
The PDF is from a search for Brick Space in this journal.
Some context: http://m759.net/wordpress/?s=Weyl+Coordinatization.
Thursday, December 19, 2024
Different Angles
"Drawing the same face from different angles sounds fun,
but let me tell you – it’s not. It’s not fun at all. It’s HARD!!"
— Loisvb on Instagram, Dec. 18, 2024
Likewise for PG(5,2).
Exercise: The eight-part diagrams in the graphic "brick space"
model of PG(5,2) below need to be suitably labeled with six-part
GF(2) coordinates to help illustrate the Klein correspondence that
underlies the large Mathieu group M24.
Tuesday, September 17, 2024
Tuesday, August 27, 2024
For Rubik Worshippers
The above is six-dimensional as an affine space, but only five-dimensional
as a projective space . . . the space PG(5, 2).
As the domain of the smallest model of the Klein correspondence and the
Klein quadric, PG (5,2) is not without mathematical importance.
See Chess Bricks and Ovid.group.
This post was suggested by the date July 6, 2024 in a Warren, PA obituary
and by that date in this journal.
Sunday, August 11, 2024
Double Duals
"That in which space itself is contained"
— Wallace Stevens
In the ninefold square,
projective-perspectivity duality
corresponds to
projective-correlation duality.
Illustrations —
Friday, July 5, 2024
De Bruyn on the Klein Quadric
— De Bruyn, Bart. “Quadratic Sets on the Klein Quadric.”
JOURNAL OF COMBINATORIAL THEORY SERIES A,
vol. 190, 2022, doi:10.1016/j.jcta.2022.105635.
Related material —
Log24 on Wednesday, July 3, 2024: "The Nutshell Miracle" . . .
In particular, within that post, my own 2019 "nutshell" diagram of PG(5,2):
PG(5,2)

Wednesday, July 3, 2024
The Nutshell Miracle
From a search in this journal for nocciolo —
From a search in this journal for PG(5,2) —
From a search in this journal for Curtis MOG —
Shown above is a rearranged version of the
Miracle Octad Generator (MOG) of R. T. Curtis
("A new combinatorial approach to M24,"
Math. Proc. Camb. Phil. Soc., 79 (1976), 25-42.)
From a search in this journal for Klein Correspondence —
The picture of PG(5,2) above as an expanded nocciolo
shows that the Miracle Octad Generator illustrates
the Klein correspondence.
Update of 10:33 PM ET Friday, July 5, 2024 —
See the July 5 post "De Bruyn on the Klein Quadric."
Tuesday, June 21, 2022
For the Church of Synchronology*
See also this journal on the above Cambridge U. Press date.
"There are many places one can read about twistors
and the mathematics that underlies them. One that
I can especially recommend is the book Twistor Geometry
and Field Theory, by Ward and Wells."
— Peter Woit, "Not Even Wrong" weblog post, March 6, 2020.
* A fictional entity. See Synchronology in this journal.
Wednesday, February 9, 2022
8!
Conwell, 1910 —
(In modern notation, Conwell is showing that the complete
projective group of collineations and dualities of the finite
3-space PG (3,2) is of order 8 factorial, i.e. "8!" —
In other words, that any permutation of eight things may be
regarded as a geometric transformation of PG (3,2).)
Later discussion of this same "Klein correspondence"
between Conwell's 3-space and 5-space . . .
A somewhat simpler toy model —
Related fiction — "The Bulk Beings" of the film "Interstellar."
Monday, January 17, 2022
Heisenberg Revisited
Sunday, October 11, 2020
Saniga on Einstein
See “Einstein on Acid” by Stephen Battersby
(New Scientist , Vol. 180, issue 2426 — 20 Dec. 2003, 40-43).
That 2003 article is about some speculations of Metod Saniga.
“Saniga is not a professional mystic or
a peddler of drugs, he is an astrophysicist
at the Slovak Academy of Sciences in Bratislava.
It seems unlikely that studying stars led him to
such a way-out view of space and time. Has he
undergone a drug-induced epiphany, or a period
of mental instability? ‘No, no, no,’ Saniga says,
‘I am a perfectly sane person.'”
Some more recent and much less speculative remarks by Saniga
are related to the Klein correspondence —
arXiv.org > math > arXiv:1409.5691:
Mathematics > Combinatorics
[Submitted on 17 Sep 2014]
The Complement of Binary Klein Quadric
as a Combinatorial Grassmannian
By Metod Saniga
“Given a hyperbolic quadric of PG(5,2), there are 28 points
off this quadric and 56 lines skew to it. It is shown that the
(286,563)-configuration formed by these points and lines
is isomorphic to the combinatorial Grassmannian of type
G2(8). It is also pointed out that a set of seven points of
G2(8) whose labels share a mark corresponds to a
Conwell heptad of PG(5,2). Gradual removal of Conwell
heptads from the (286,563)-configuration yields a nested
sequence of binomial configurations identical with part of
that found to be associated with Cayley-Dickson algebras
(arXiv:1405.6888).”
Related entertainment —
See Log24 on the date, 17 Sept. 2014, of Saniga’s Klein-quadric article:
Wednesday, September 16, 2020
Critical Invisibility
Synchronology check —
This journal on the above dates —
8 January 2019 (“For the Church of Synchronology“)
and 24 April 2019 (“Critical Visibility“).
Related mathematics: Klein Correspondence posts.
Related entertainment: “The Bulk Beings.”
The above Physical Review remarks were found in a search
for a purely mathematical concept —
Sunday, December 29, 2019
Articulation Raid
“… And so each venture Is a new beginning,
a raid on the inarticulate….”
— T. S. Eliot, “East Coker V” in Four Quartets
|
arXiv:1409.5691v1 [math.CO] 17 Sep 2014
The Complement of Binary Klein Quadric as
Metod Saniga, Abstract
Given a hyperbolic quadric of PG(5, 2), there are 28 points off this quadric and 56 lines skew to it. It is shown that the Keywords:
Combinatorial Grassmannian − |
See also this journal on the above date — 17 September 2014.
Wednesday, December 11, 2019
Klein Quadric
The architecture of the recent post
Geometry of 6 and 8 is in part
a reference to the Klein quadric.
Thursday, June 28, 2018
Monday, May 28, 2018
Skewers
A piece co-written by Ivanov, the author noted in the previous post, was cited
in my "Geometry of the 4×4 Square."
Also cited there — A paper by Pasini and Van Maldeghem that mentions
the Klein quadric.
Those sources suggested a search —
The link is to some geometry recently described by Tabachnikov
that seems rather elegant:
For another, more direct, connection to the geometry of the 4×4 square,
see Richard Evan Schwartz in this journal.
This same Schwartz appears also in the above Tabachnikov paper:

Tuesday, April 3, 2018
Easter at Cambridge
Thursday, July 6, 2017
A Pleasing Situation
The 4x4x4 cube is the natural setting
for the finite version of the Klein quadric
and the eight "heptads" discussed by
Conwell in 1910.
As R. Shaw remarked in 1995,
"The situation is indeed quite pleasing."









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