What is...a Hadamard matrix?

Опубликовано: 21 Май 2026
на канале: VisualMath

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Goal.
I would like to tell you a bit about my favorite theorems, ideas or concepts in mathematics and why I like them so much.

This time.
What is...a Hadamard matrix? Or: Orthogonality exists! Or not?

Disclaimer.
Nobody is perfect, and I might have said something silly. If there is any doubt, then please check the references.

Sorry.
Somehow the picture froze. Not the slides though and I guess you do not need to see me anyway ;-)

Slides.
http://www.dtubbenhauer.com/youtube.html

Thumbnail.
Picture from https://demonstrations.wolfram.com/Sm...

Main discussion.
https://en.wikipedia.org/wiki/Hadamar...
https://mathworld.wolfram.com/Hadamar...
https://nhigham.com/2020/04/10/what-i...
https://oeis.org/search?q=Hadamard+Ma...
https://en.wikipedia.org/wiki/Walsh_m...
https://en.wikipedia.org/wiki/Quincun...
https://rangevoting.org/SkewHad.html
https://mathworld.wolfram.com/PaleyCo...
https://www.sciencedirect.com/science...

Background.
https://projecteuclid.org/journals/an...
https://en.wikipedia.org/wiki/Hadamar...
https://en.wikipedia.org/wiki/Combina...
https://en.wikipedia.org/wiki/Quantum...
http://neilsloane.com/hadamard/

Mathematica.
https://demonstrations.wolfram.com/Sm...
https://demonstrations.wolfram.com/Ya...

Pictures used.
https://www.cs.princeton.edu/courses/...
Picture from https://demonstrations.wolfram.com/Sm...
More pictures from https://demonstrations.wolfram.com/Sm...
Even more pictures from https://demonstrations.wolfram.com/Sm...
Picture using Mathematica Plot

YouTube and co.
   • Video
   • Hadamard Matrices - Raymond Jin
   • Hadamard Matrices Lect.-01 || Hadamard Mat...

#combinatorics
#linearalgebra
#mathematics