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Saturday, October 24, 2020

The Galois Tesseract

Filed under: General — Tags: — m759 @ 9:32 AM

Stanley E. Payne and J. A. Thas in 1983* (previous post) —

“… a 4×4 grid together with
the affine lines on it is AG(2,4).”

Payne and Thas of course use their own definition
of affine lines on a grid.

Actually, a 4×4 grid together with the affine lines on it
is, viewed in a different way, not AG(2,4) but rather AG(4,2).

For AG(4,2) in the proper context, see
Affine Groups on Small Binary Spaces and
The Galois Tesseract.

* And 26 years later,  in 2009.

Grids

Filed under: General — Tags: — m759 @ 9:00 AM

Wikipedia on what has been called “the doily” —

“The smallest non-trivial generalized quadrangle
is GQ(2,2), whose representation* has been dubbed
‘the doily’ by Stan Payne in 1973.”

A later publication relates the doily to grids.

From Finite Generalized Quadrangles , by Stanley E. Payne
and J. A. Thas, December 1983, at researchgate.net, pp. 81-82—

“Then the lines … define a 3×3 grid G  (i.e. a grid
consisting of 9 points and 6 lines).”
. . . .
“So we have shown that the grid G  can completed [sic ]
in a unique way to a grid with 8 lines and 16 points.”
. . . .
“A 4×4 grid defines a linear subspace
of  the 2−(64,4,1) design, i.e. a 4×4 grid
together with the affine lines on it is AG(2,4).”

A more graphic approach from this journal —

Seven is Heaven...

Click the image for further details.

* This wording implies that GQ(2,2) has a unique
visual representation. It does not. See inscape .

Friday, October 23, 2020

Language Game:  The Doily Curse

Filed under: General — Tags: , — m759 @ 5:01 PM

“Quadrangle” is also a mathematical term.

Example: The Doily.

See also  The Crosswicks Curse .

Sunday, October 18, 2020

Unfolded

Filed under: General — Tags: , — m759 @ 5:10 AM

See “Unfolded.jpg” in this journal.  From that search —

Pentagon with pentagram    

Compare and contrast these figures with images by Wittgenstein in . . .

Wittgenstein's pentagram and 4x4 'counting-pattern'

Related material from last night’s post Modernist Cuts

Schlick also appears in recent posts tagged Moriarty Variations.

Wednesday, October 7, 2020

Between Pyramid and Pentagon

Filed under: General — Tags: — m759 @ 12:34 AM

The 35 small squares between the pyramid and the pentagon
in the above search result illustrate the role of finite geometry
in the Miracle Octad Generator  of R. T. Curtis.

'Then a miracle occurs' cartoon

Cartoon by S. Harris

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