Log24

Friday, March 26, 2021

Sex Textiles: Introduction to Symplectic* Finite Geometry

Filed under: General — Tags: — m759 @ 11:13 pm

'The Eddington Song'

Another concept from The New York Times  today: intertwining

“The historical achievements and experiences of women and men
are like the intertwined warp and weft threads of a woven fabric.”

— Virginia Postrel in a NY Times  opinion piece today.

From Postrel’s Web page

* See (for instance) A Picture Show for Quanta Magazine.

Sunday, August 2, 2015

Symplectic

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

See "Symplectic" in this journal.  Some illustrations —

 

Midrash —

"Adorned with cryptic stones and sliding shines,
An immaculate personage in nothingness,
With the whole spirit sparkling in its cloth,

Generations of the imagination piled
In the manner of its stitchings, of its thread,
In the weaving round the wonder of its need,

And the first flowers upon it, an alphabet
By which to spell out holy doom and end,
A bee for the remembering of happiness."

— Wallace Stevens, "The Owl in the Sarcophagus"

Friday, January 23, 2015

Complex Symplectic Fantasy

Filed under: General — Tags: — m759 @ 8:08 pm

"We are not isolated free chosers,
monarchs of all we survey, but
benighted creatures sunk in a reality
whose nature we are constantly and
overwhelmingly tempted to deform
by fantasy."

—Iris Murdoch, "Against Dryness"
in Encounter , p. 20 of issue 88 
(vol. 16 no. 1, January 1961, pp. 16-20)

"We need to turn our attention away from the consoling
dream necessity of Romanticism, away from the dry
symbol, the bogus individual, the false whole, towards
the real impenetrable human person."

— Iris Murdoch, 1961

"Impenetrability!  That's what I  say!"

Humpty Dumpty, 1871

Friday, November 14, 2014

Some Symplectic History

Filed under: General,Geometry — m759 @ 1:28 am

A paper from 1976 on symplectic torsors  and finite geometry:

IMAGE- Saavedra-Rivano, 'Finite Geometries in the Theory of Theta Characteristics' (1976)

A pdf is now available:

FINITE GEOMETRIES IN THE THEORY OF THETA CHARACTERISTICS
Autor(en): Rivano, Neantro Saavedra
Objekttyp: Article
Zeitschrift: L’Enseignement Mathématique
Band (Jahr): 22 (1976)
Heft 1-2: L’ENSEIGNEMENT MATHÉMATIQUE
PDF erstellt am: 14.11.2014
Persistenter Link: http://dx.doi.org/10.5169/seals-48185

(Received by the journal on February 20, 1976.)

Saavedra-Rivano was a student of Grothendieck, who reportedly died yesterday.

Saturday, September 20, 2014

Symplectic Structure

Filed under: General,Geometry — Tags: — m759 @ 11:30 am

(Continued)

The fictional zero theorem  of Terry Gilliam's current film
by that name should not be confused with the zero system
underlying the diamond theorem.

Sunday, August 24, 2014

Symplectic Structure…

In the Miracle Octad Generator (MOG):

The above details from a one-page note of April 26, 1986, refer to the
Miracle Octad Generator of R. T. Curtis, as it was published in 1976:

http://www.log24.com/log/pix10A/100514-Curtis1976MOG.jpg

From R. T. Curtis (1976). A new combinatorial approach to M24,
Mathematical Proceedings of the Cambridge Philosophical Society ,
79, pp 25-42. doi:10.1017/S0305004100052075.

The 1986 note assumed that the reader would be able to supply, from the
MOG itself, the missing top row of each heavy brick.

Note that the interchange of the two squares in the top row of each
heavy brick induces the diamond-theorem correlation.

Note also that the 20 pictured 3-subsets of a 6-set in the 1986 note
occur as paired complements  in two pictures, each showing 10 of the
3-subsets.

This pair of pictures corresponds to the 20 Rosenhain tetrads  among
the 35 lines of PG(3,2), while the picture showing the 2-subsets
corresponds to the 15 Göpel tetrads  among the 35 lines.

See Rosenhain and Göpel tetrads in PG(3,2). Some further background:

Wednesday, August 13, 2014

Symplectic Structure continued

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

Some background for the part of the 2002 paper by Dolgachev and Keum
quoted here on January 17, 2014 —

Related material in this journal (click image for posts) —

Monday, August 11, 2014

Syntactic/Symplectic

(Continued from August 9, 2014.)

Syntactic:

Symplectic:

"Visual forms— lines, colors, proportions, etc.— are just as capable of
articulation , i.e. of complex combination, as words. But the laws that govern
this sort of articulation are altogether different from the laws of syntax that
govern language. The most radical difference is that visual forms are not
discursive 
. They do not present their constituents successively, but
simultaneously, so the relations determining a visual structure are grasped
in one act of vision."

– Susanne K. LangerPhilosophy in a New Key

For examples, see The Diamond-Theorem Correlation
in Rosenhain and Göpel Tetrads in PG(3,2).

This is a symplectic  correlation,* constructed using the following
visual structure:

IMAGE- A symplectic structure -- i.e. a structure that is symplectic (meaning plaited or woven).

* Defined in (for instance) Paul B. Yale, Geometry and Symmetry ,
Holden-Day, 1968, sections 6.9 and 6.10.

Saturday, August 9, 2014

Syntactic/Symplectic

Filed under: General,Geometry — Tags: — m759 @ 3:00 pm

Syntactic  Structure —

See the Lightfoot of today's previous post:

Symplectic  Structure —

See the plaited, or woven, structure of  August 6:

IMAGE- A symplectic structure -- i.e. a structure that is symplectic (meaning plaited or woven).

See also Deep  Structure  (Dec. 9, 2012).

Wednesday, August 6, 2014

Symplectic Structure*

Filed under: General,Geometry — Tags: — m759 @ 1:00 pm

From Gotay and Isenberg, "The Symplectization of Science,"
Gazette des Mathématiciens  54, 59-79 (1992):

"… what is the origin of the unusual name 'symplectic'? ….
Its mathematical usage is due to Hermann Weyl who,
in an effort to avoid a certain semantic confusion, renamed
the then obscure 'line complex group' the 'symplectic group.'
… the adjective 'symplectic' means 'plaited together' or 'woven.'
This is wonderfully apt…."

IMAGE- A symplectic structure -- i.e. a structure that is symplectic (meaning plaited or woven)

The above symplectic  structure** now appears in the figure
illustrating the diamond-theorem correlation in the webpage
Rosenhain and Göpel Tetrads in PG(3,2).

Some related passages from the literature:

http://www.log24.com/log/pix10B/100915-SteinbergOnChevalleyGroups.jpg

* The title is a deliberate abuse of language .
For the real definition of "symplectic structure," see (for instance)
"Symplectic Geometry," by Ana Cannas da Silva (article written for
Handbook of Differential Geometry, vol 2.) To establish that the
above figure is indeed symplectic , see the post Zero System of
July 31, 2014.

** See Steven H. Cullinane, Inscapes III, 1986

Thursday, August 14, 2025

The Klein Quadric and 105 Lines

Filed under: General — Tags: , — m759 @ 7:20 pm

Earlier Log24 posts tagged 105 Partitions suggest a look at . . .

Version 4 of the above paper is at https://arxiv.org/abs/2105.13798.

See also this  journal on the Version 2 date — April 9, 2022 —
a post titled Academic Rhetoric on visual diagrams in mathematics.

Saturday, August 26, 2023

Jing

Filed under: General — Tags: — m759 @ 12:40 am

The previous post suggests a reading:

"The Chinese word for 'sacred texts' is jing  經, a character
having its etymological origin in textiles. The first meaning
of this character denotes the fixed lead thread or warp of cloth,
insofar as the weft threads are woven into warp threads to
make a fabric. Its extended meaning referes to authority,
orthodoxy, and the essential way toward truth and principle." 

— Page 497, Yanrong Chen,  "Christian Biblical Tradition in 
the Jing Chinese Culture," Oxford Handbook of the Bible 
in China
, edited by K. K. Yeo, Oxford U. Press, 2021.

See as well the non-Chinese word "symplectic" in this  journal.

Wednesday, August 9, 2023

The Junction Function

Filed under: General — Tags: , — m759 @ 12:27 pm

A function (in this case, a 1-to-1 correspondence) from finite geometry:

IMAGE- The natural symplectic polarity in PG(3,2), illustrating a symplectic structure

This correspondence between points and hyperplanes underlies
the symmetries discussed in the Cullinane diamond theorem.

Academics who prefer cartoon graveyards may consult …

Cohn, N. (2014). Narrative conjunction’s junction function:
A theoretical model of “additive” inference in visual narratives. 
Proceedings of the Annual Meeting of the Cognitive Science
Society
, 36. See https://escholarship.org/uc/item/2050s18m .

Thursday, June 15, 2023

Michaelmas 2019

Filed under: General — Tags: , — m759 @ 1:06 pm

Transcribed from a PDF:

Received September 29, 2019, accepted October 15, 2019,
date of publication October 24, 2019, date of current version
November 7, 2019.

Digital Object Identifier 10.1109/ACCESS.2019.2949310

A Method for Determining
the Affine Equivalence of Boolean Functions

ZIYU WANG1 , XIAO ZENG1 , JINZHAO WU2,3, AND
GUOWU YANG1

1Big Data Research Center, School of Computer Science
and Engineering, University of Electronic Science and Technology
of China, Chengdu 611731, China

2Guangxi Key Laboratory of Hybrid Computation and
IC Design Analysis, Guangxi University for Nationalities,
Nanning 530006, China

3School of Computer and Electronic Information,
Guangxi University, Nanning 530004, China

Corresponding authors:
Jinzhao Wu (gxmdwjzh@aliyun.com) and
Guowu Yang (ygwuestc@163.com)

This work was supported in part by the National Natural Science Foundation
of China under Grant 61772006 and Grant 61572109, in part by the
State Key Laboratory of Information Security, Institute of Information Engineering, 
Chinese Academy of Sciences, Beijing, in part by the Science and Technology
Program of Guangxi  under Grant AB17129012, in part by the Science and
Technology Major Project of Guangxi under Grant AA17204096, in part by 
the Special Fund for Scientific and Technological Bases and Talents
of Guangxi under Grant 2016AD05050, and in part by the Special Fund for
Bagui Scholars of Guangxi, in part by the Open fund of State Key Laboratory 
of Information Security.

ABSTRACT 
Determining the affine equivalence of Boolean functions
has significant applications in circuit and cryptography.
Previous methods for determining this require a large
amount of computation when Boolean functions are bent
functions or when the truth table is sparse. This paper
presents a new method to determine the affine equivalence
based on matrix algebra. By transforming Boolean function
to the corresponding matrix representation, we first propose
and prove the congruent standard form of Boolean function.
It lays the foundation for the determination of equivalence
because affine Boolean functions must have the same
standard form. Then we find the generators of orthogonal
matrix group and symplectic matrix group, which greatly
reduce the search space. The computation complexity of
our method is o (2r2/2+n∗(nr) ), where is the number of
bit operations, and r  is the rank of the matrix, which is
the product of Boolean-1 matrix of the test Boolean function
and its transposition. The experimental results show that our
method is useful when the test Boolean function is no more
than 7 bits and r  is greater than 2.

INDEX TERMS  Logic synthesis, Boolean functions,
affine equivalence, matrix group, algorithm.

Meanwhile . . .

Sunday, September 4, 2022

Dice and the Eightfold Cube

Filed under: General — Tags: , , , , — m759 @ 4:47 pm

At Hiroshima on March 9, 2018, Aitchison discussed another
"hexagonal array" with two added points… not at the center, as
in the Gell-Mann picture above, but rather at the ends  of one of
a cube's four diagonal axes of symmetry.

See some related illustrations below. 

Fans of the fictional "Transfiguration College" in the play
"Heroes of the Fourth Turning" may recall that August 6,
another Hiroshima date, was the Feast of the Transfiguration.

Iain Aitchison's 'dice-labelled' cuboctahedron at Hiroshima, March 2018

The exceptional role of  0 and  in Aitchison's diagram is echoed
by the occurence of these symbols in the "knight" labeling of a 
Miracle Octad Generator octad —

Transposition of  0 and  in the knight coordinatization 
induces the symplectic polarity of PG(3,2) discussed by 
(for instance) Anne Duncan in 1968.

Friday, September 2, 2022

History of Mathematics

Filed under: General — m759 @ 2:54 pm

Anne Duncan in 1968 on a 1960 paper by Robert Steinberg —


_______________________________________________________________________________

Related remarks in this  journal — Steinberg + Chevalley.

Related illustrations in this journal — 4×4.

Related biographical remarksSteinberg Deathdate.

Tuesday, November 16, 2021

Wrap Party

Filed under: General — m759 @ 3:23 am

Art Date:

"The serpent's eyes shine
As he wraps around the vine"
— Don Henley, The Garden of Allah

Thursday, July 30, 2020

A Picture Show for Quanta Magazine

Filed under: General — Tags: , , , — m759 @ 8:33 am

An article yesterday at Quanta Magazine  suggests a review . . .

From Diamond Theorem  images at Pinterest —

Some background —

Wednesday, January 15, 2020

Paradigm Shift

Filed under: General — Tags: — m759 @ 1:33 pm

Sheehan, 'Making Sense of Heidegger,' p. 39

Illustration, from a search in this journal for “Symplectic” —

IMAGE- A symplectic structure -- i.e. a structure that is symplectic (meaning plaited or woven).

Some background:  Rift-design  in this journal and

Tuesday, January 7, 2020

Invisible Weaving

Filed under: General — Tags: — m759 @ 10:13 am

See as well a post from this journal on the above date
June 12, 2014. (That post revisits a post from today's  date —
January 7 — eight years ago, in 2012.)

Related material:  Dharma Fabric and Symplectic.

Wednesday, September 25, 2019

Before Personalities …

Filed under: General — Tags: — m759 @ 6:10 pm

Tuesday, April 23, 2019

Critical Invisibility

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

From Gotay and Isenberg, "The Symplectization of Science,"
Gazette des Mathématiciens  54, 59-79 (1992):

" what is the origin of the unusual name 'symplectic'? ….
Its mathematical usage is due to Hermann Weyl who,
in an effort to avoid a certain semantic confusion, renamed
the then obscure 'line complex group' the 'symplectic group.'
… the adjective 'symplectic' means 'plaited together' or 'woven.'
This is wonderfully apt…."

On "The Emperor's New Clothes" —

Andersen’s weavers, as one commentator points out, are merely insisting that “the value of their labor be recognized apart from its material embodiment.” The invisible cloth they weave may never manifest itself in material terms, but the description of its beauty (“as light as spiderwebs” and “exquisite”) turns it into one of the many wondrous objects found in Andersen’s fairy tales. It is that cloth that captivates us, making us do the imaginative work of seeing something beautiful even when it has no material reality. Deeply resonant with meaning and of rare aesthetic beauty—even if they never become real—the cloth and other wondrous objets d’art have attained a certain degree of critical invisibility.

—  Maria Tatar, The Annotated Hans Christian Andersen  (W. W. Norton & Company, 2007). Kindle Edition. 

Tuesday, February 26, 2019

Citation

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

Some related material in this journal — See a search for k6.gif.

Some related material from Harvard —

Elkies's  "15 simple transpositions" clearly correspond to the 15 edges of
the complete graph K6 and to the 15  2-subsets of a 6-set.

For the connection to PG(3,2), see Finite Geometry of the Square and Cube.

The following "manifestation" of the 2-subsets of a 6-set might serve as
the desired Wikipedia citation —

See also the above 1986 construction of PG(3,2) from a 6-set
in the work of other authors in 1994 and 2002 . . .

IMAGE- Dolgachev and Keum, coordinatization of the 4x4 array in 'Birational Automorphisms of Quartic Hessian Surfaces,' AMS Transactions, 2002

Tuesday, June 19, 2018

Death on Father’s Day

Filed under: General — m759 @ 8:45 pm

From the University of Notre Dame in an obituary dated June 17

Timothy O’Meara, provost emeritus, Kenna Professor of Mathematics Emeritus and Trustee Emeritus at the University of Notre Dame, died June 17. He was 90.

A member of the Notre Dame faculty since 1962, O’Meara twice served as chairman of the University’s mathematics department and served as its first lay provost from 1978 to 1996.
. . . .         

He was graduated from the University of Cape Town in 1947 and earned a master’s degree in mathematics there the following year.  Earning his doctoral degree from Princeton University in 1953, he taught at the University of Otago in New Zealand from 1954 to 1956 before returning to Princeton where he served on the mathematics faculty and as a member of the Institute for Advanced Study for the next six years.  
. . . .

In addition to his mathematical teaching and scholarship, he published magisterial works, including “Introduction to Quadratic Forms,” “Lectures on Linear Groups,” “Symplectic Groups” and “The Classical Groups and K-Theory,” co-authored with Alexander J. Hahn, professor of mathematics emeritus at Notre Dame and a former O’Meara doctoral student.
. . . .

Related material (update of 9:20 PM ET on June 19) —

Sunday, December 10, 2017

Geometry

Google search result for Plato + Statesman + interlacing + interweaving

See also Symplectic in this journal.

From Gotay and Isenberg, “The Symplectization of Science,”
Gazette des Mathématiciens  54, 59-79 (1992):

“… what is the origin of the unusual name ‘symplectic’? ….
Its mathematical usage is due to Hermann Weyl who,
in an effort to avoid a certain semantic confusion, renamed
the then obscure ‘line complex group’ the ‘symplectic group.’
… the adjective ‘symplectic’ means ‘plaited together’ or ‘woven.’
This is wonderfully apt….”

IMAGE- A symplectic structure -- i.e. a structure that is symplectic (meaning plaited or woven)

The above symplectic  figure appears in remarks on
the diamond-theorem correlation in the webpage
Rosenhain and Göpel Tetrads in PG(3,2). See also
related remarks on the notion of  linear  (or line ) complex
in the finite projective space PG(3,2) —

Anticommuting Dirac matrices as spreads of projective lines

Ron Shaw on the 15 lines of the classical generalized quadrangle W(2), a general linear complex in PG(3,2)

Friday, April 14, 2017

Hudson and Finite Geometry

Filed under: General,Geometry — Tags: , , — m759 @ 3:00 am

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

The above four-element sets of black subsquares of a 4×4 square array 
are 15 of the 60 Göpel tetrads , and 20 of the 80 Rosenhain tetrads , defined
by R. W. H. T. Hudson in his 1905 classic Kummer's Quartic Surface .

Hudson did not  view these 35 tetrads as planes through the origin in a finite
affine 4-space (or, equivalently, as lines in the corresponding finite projective
3-space).

In order to view them in this way, one can view the tetrads as derived,
via the 15 two-element subsets of a six-element set, from the 16 elements
of the binary Galois affine space pictured above at top left.

This space is formed by taking symmetric-difference (Galois binary)
sums of the 15 two-element subsets, and identifying any resulting four-
element (or, summing three disjoint two-element subsets, six-element)
subsets with their complements.  This process was described in my note
"The 2-subsets of a 6-set are the points of a PG(3,2)" of May 26, 1986.

The space was later described in the following —

IMAGE- Dolgachev and Keum, coordinatization of the 4x4 array in 'Birational Automorphisms of Quartic Hessian Surfaces,' AMS Transactions, 2002

Wednesday, February 15, 2017

Warp and Woof

Filed under: General,Geometry — m759 @ 3:00 pm

Space —

Space structure —

From Gotay and Isenberg, “The Symplectization of Science,”
Gazette des Mathématiciens  54, 59-79 (1992):

“… what is the origin of the unusual name ‘symplectic’? ….
Its mathematical usage is due to Hermann Weyl who,
in an effort to avoid a certain semantic confusion, renamed
the then obscure ‘line complex group’ the ‘symplectic group.’
… the adjective ‘symplectic’ means ‘plaited together’ or ‘woven.’
This is wonderfully apt….”

IMAGE- A symplectic structure -- i.e. a structure that is symplectic (meaning plaited or woven)

The above symplectic  figure appears in remarks on
the diamond-theorem correlation in the webpage
Rosenhain and Göpel Tetrads in PG(3,2).

Space shuttle —

Related ethnic remarks —

As opposed to Michael  Larsen —

Funny, you don't look  Danish.

Wednesday, November 23, 2016

Yogiism

Filed under: General,Geometry — Tags: , — m759 @ 12:31 pm

From the American Mathematical Society (AMS) webpage today —

From the current AMS Notices

Related material from a post of Aug. 6, 2014

http://www.log24.com/log/pix10B/100915-SteinbergOnChevalleyGroups.jpg

(Here "five point sets" should be "five-point sets.")

From Gotay and Isenberg, “The Symplectization of Science,”
Gazette des Mathématiciens  54, 59-79 (1992):

“… what is the origin of the unusual name ‘symplectic’? ….
Its mathematical usage is due to Hermann Weyl who,
in an effort to avoid a certain semantic confusion, renamed
the then obscure ‘line complex group’ the ‘symplectic group.’
… the adjective ‘symplectic’ means ‘plaited together’ or ‘woven.’
This is wonderfully apt….”

IMAGE- A symplectic structure -- i.e. a structure that is symplectic (meaning plaited or woven)

The above symplectic  structure* now appears in the figure
illustrating the diamond-theorem correlation in the webpage
Rosenhain and Göpel Tetrads in PG(3,2).

* The phrase as used here is a deliberate 
abuse of language .  For the real definition of 
“symplectic structure,” see (for instance) 
“Symplectic Geometry,” by Ana Cannas da Silva
(article written for Handbook of Differential
Geometry 
, Vol 2.) To establish that the above
figure is indeed symplectic , see the post 
Zero System of July 31, 2014.

Friday, September 16, 2016

A Counting-Pattern

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

Wittgenstein, 1939

Dolgachev and Keum, 2002

IMAGE- Dolgachev and Keum, coordinatization of the 4x4 array in 'Birational Automorphisms of Quartic Hessian Surfaces,' AMS Transactions, 2002

For some related material, see posts tagged Priority.

Monday, September 12, 2016

The Kummer Lattice

The previous post quoted Tom Wolfe on Chomsky's use of
the word "array." 

An example of particular interest is the 4×4  array
(whether of dots or of unit squares) —

      .

Some context for the 4×4 array —

The following definition indicates that the 4×4 array, when
suitably coordinatized, underlies the Kummer lattice .

Further background on the Kummer lattice:

Alice Garbagnati and Alessandra Sarti, 
"Kummer Surfaces and K3 surfaces
with $(Z/2Z)^4$ symplectic action." 
To appear in Rocky Mountain J. Math.

The above article is written from the viewpoint of traditional
algebraic geometry. For a less traditional view of the underlying
affine 4-space from finite  geometry, see the website
Finite Geometry of the Square and Cube.

Some further context

"To our knowledge, the relation of the Golay code
to the Kummer lattice is a new observation."

— Anne Taormina and Katrin Wendland,
"The overarching finite symmetry group of
Kummer surfaces in the Mathieu group M24 
"

As noted earlier, Taormina and Wendland seem not to be aware of
R. W. H. T. Hudson's use of the (uncoordinatized*) 4×4 array in his
1905 book Kummer's Quartic Surface.  The array was coordinatized,
i.e. given a "vector space structure," by Cullinane eight years prior to
the cited remarks of Curtis.

* Update of Sept. 14: "Uncoordinatized," but parametrized  by 0 and
the 15 two-subsets of a six-set. See the post of Sept. 13.

Older Posts »

Powered by WordPress