#combinatorics

2026-02-05

Two ways of cutting an infinite 3-periodic heptagonal tiling along higher order modules.

Module 1 of 2.

#tiling #geometry #math #3d #combinatorics

2026-01-29

RE: mastoxiv.page/@arXiv_mathCO_bo

Here is the second manuscript coming out of the "Topics in Ramsey theory" online-only problem-solving session (sparse-graphs.mimuw.edu.pl/dok) of the Sparse (Graphs) Coalition, which took place less than a year ago.

The first manuscript already came out a couple months earlier (arxiv.org/abs/2510.17981).

Both have made serious progress in serious Erdős problems.

#combinatorics #remoteconferences #graphtheory #extremalcombinatorics #erdős

2026-01-28

“I feel that many women, especially in India, might not know what exactly having a career in maths actually means or even that they can pursue a career in this field. I believe it is important to tell them that this is an option.” - Nishu Kumari

➡️hermathsstory.eu/nishu-kumari/

#Academia #Combinatorics #Europe #Mathematics #PhD #Postdoc

Portrait of Nishu Kumari, postdoc researcher at the University of Vienna. She has black hair, wears glasses and a red patterned blouse, and sits under a tree against the backdrop of an entrance to a building. The image includes the Her Maths Story logo and her name and title.
2026-01-27

#ThisWeeksFiddler, 20260123
This week the #puzzle is: Bingo! #statistics #probabilities #combinatorics #counting #coding #program #montecarlo A game of bingo typically consists of a 5-by-5 grid with 25 total squares. Each square (except for the center square) contains a number. When a square’s number is called, you place a marker on that square. The goal is to get […]

stuff.ommadawn.dk/2026/01/27/t

2026-01-26

And a more solid representation illustrates how the tiles fit together even better.

(4/n)

#tilingTuesday #math #3d #geometry #combinatorics

2026-01-26

This 11-gon forms the surface.

(3/n) #tilingTuesday #math #3d #geometry #combinatorics

2026-01-26

4 tiles form a module.

(2/n) #tilingTuesday #math #3d #geometry #combinatorics

2026-01-26

Nicely twisted excerpt of a monohedral 11-gon tiling of a non-compact surface embedded in 𝑅³. (3 11-gons at every vertex)

The surface shows two periodic growth and the labeled dual edges of the tiling form a partial Cayley surface complex of the group:

G = ⟨ f₁, f₂, f₃, t₁, t₂, t₃, t₄ ∣ f₁², f₂², f₃², t₄³, t₁³, t₃⁶, (t₁t₄⁻¹)⁹, f₃t₂, t₁t₃t₂, (f₁t₁)², f₃t₃t₄⁻¹ ⟩

(1/n) #tilingTuesday #math #3d #geometry #combinatorics

Dyalogdyalog
2026-01-19

2014-06: Write a function that takes an integer vector representing the sides of a number of dice and returns a 2 column matrix of the number of ways each possible total of the dice can be rolled (see apl.quest/2014/6/ to test your solution and view ours).

2026-01-07

Riffs and Rotes • Happy New Year 2026
inquiryintoinquiry.com/2026/01

There's a deep mathematical significance I see in the following structures, and I'm hoping one day to find a way to explain all the things I see there. Meanwhile, you may take them as an amusing diversion in recreational maths.

\( \text{Let} ~ p_n = \text{the} ~ n^\text{th} ~ \text{prime}. \)

\( \begin{array}{llcl}
\text{Then} & 2026 & = & 2 \cdot 1013
\\
&& = & p_1 p_{170}
\\
&& = & p_1 p_{2 \cdot 5 \cdot 17}
\\
&& = & p_1 p_{p_1 p_3 p_7}
\\
&& = & p_1 p_{p_1 p_{p_2} p_{p_4}}
\\
&& = & p_1 p_{p_1 p_{p_{p_1}} p_{p_{{p_1}^{p_1}}}}
\end{array} \)

No information is lost by dropping the terminal 1s. Thus we may write the following form.

\[ 2026 = p p_{p p_{p_p} p_{p_{p^p}}} \]

The article linked below tells how forms of that order correspond to a family of digraphs called “riffs” and a family of graphs called “rotes”.

The riff and rote for 2026 are shown in the next two Figures.

Riff 2026
inquiryintoinquiry.com/wp-cont

Rote 2026
inquiryintoinquiry.com/wp-cont

Reference —

Riffs and Rotes
oeis.org/wiki/Riffs_and_Rotes

cc: academia.edu/community/VBA6Qz
cc: researchgate.net/post/Riffs_an

#Arithmetic #Combinatorics #Computation #Factorization #GraphTheory #GroupTheory
#Logic #Mathematics #NumberTheory #Primes #Recursion #Representation #RiffsAndRotes

Charlotte Atencaten@videos.trom.tf
2026-01-02

Monoid representations and partitions (Charlotte Aten at DU Algebra and Logic Seminar 2023)

videos.trom.tf/w/65QpmvUhdkwDh

Jan Marthedal Rasmussenjanmr@mathstodon.xyz
2025-12-30

Bell numbers, the number of ways to partition a set of labeled elements janmr.com/posts/bell-numbers/ #math #combinatorics #bell #numbers

\[
\begin{aligned}
&\{\{k_1,k_2,k_3\}\} \\
&\{\{k_1,k_2\}, \{k_3\}\} \\
&\{\{k_1,k_3\}, \{k_2\}\} \\
&\{\{k_2,k_3\}, \{k_1\}\} \\
&\{\{k_1\}, \{k_2\}, \{k_3\}\} \\
\end{aligned}
\]

2025-12-23

Advent of Tilings - Day 24

Happy Holidays, and best wishes for a 2026 filled with imagination, curiosity and discovery!

#math #geometry #3d #combinatorics #tiling #AdventOfTilings

2025-12-22

Advent of Tilings - Day 23.2

Another one rule wonder…

f₁t₁f₁t₂t₁⁻¹t₂

#math #geometry #3d #combinatorics #tiling #AdventOfTilings #TilingTuesday

2025-12-22

Advent of Tilings - Day 23.1

Almost at the end we see the light through diamond and hexagon shaped tunnels of an infinite surface, again monohedrally tiled.

#math #geometry #3d #combinatorics #tiling #AdventOfTilings #TilingTuesday

2025-12-22

Advent of Tilings - Day 22.2

It takes only one rule to get from single tile to cuboid

f₁f₂t₁t₂⁻¹t₁f₁t₁⁻¹

#math #geometry #3d #combinatorics #tiling #AdventOfTilings

2025-12-22

Advent of Tilings - Day 22.1

It is not always easy to find a symmetric tree, but keep it in a pot and you may be surprised by what it grows up to be.

#math #geometry #3d #combinatorics #tiling #AdventOfTilings

2025-12-21

Advent of Tilings - Day 21.2

The looping rules seem to reflect the strictness of the construction:

(f₂t₁t₂)²
(f₁t₁t₁)²

#math #geometry #3d #combinatorics #tiling #AdventOfTilings

2025-12-21

Advent of Tilings - Day 21.1

This tiling grows following a double pyramid shape that would make Djoser proud. Embeddable and monohedral.

#math #geometry #3d #combinatorics #tiling #AdventOfTilings

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