P versus NP problem by Ciro Santilli 37 Updated 2025-07-16
Interesting because of the Cook-Levin theorem: if only a single NP-complete problem were in P, then all NP-complete problems would also be P!
We all know the answer for this: either false or independent.
Since that is a symmetric bilinear form, the associated matrix is a symmetric matrix.
By default, we will use the time negative representation unless stated otherwise:
but another equivalent one is to use a time positive representation:
The matrix is typically denoted by the Greek letter eta.
Pion by Ciro Santilli 37 Updated 2025-07-16
Conceptually the simplest mesons. All of them have neutral color charge:
  • charged: down + anti-up or up + anti-down, therefore with net electrical charge electron charge
  • neutral: down + anti-down or up + anti-up, therefore with net electrical charge 0
However, many, many, many terrible horrors come with it:
Optical fiber by Ciro Santilli 37 Updated 2025-07-16
Video 1.
The Story of Light by Bell Labs (2015)
Source. Gives some ideas of the history of fiber optics. Features: Herwig Kogelnik.
Video 2.
Fiber optic cables by EngineerGuy
. Source.
Video 3.
Fiber optics fundamentals by Shaoul Ezekiel
. Source. 2008 at MIT. Theory and demonstration.
Solexa by Ciro Santilli 37 Updated 2025-07-16
This is one of the prime examples of Europe's decline.
Instead of trying to dominate the sequencing market and gain trillions of dollars from it, they local British early stage investors were more than happy to get a 20x return on their small initial investments, and sold out to the Americans who will then make the real profit.
And now Solexa doesn't even have its own Wikipedia page, while Illumina is set out to be the next Microsoft. What a disgrace.
Cambridge visitors can still visit the Panton Arms pub, which was the location of the legendary "hey we should talk" founders meeting, chosen due to its proximity to the chemistry department of the University of Cambridge.
In 2021 the founders were awarded the Breakthrough Prize. The third person awarded was Pascal Mayer. He was apparently at Serono Pharmaceutical Research Institute at the time of development. They do have a wiki page unlike Solexa: en.wikipedia.org/wiki/Serono. They paid a 700 million fine in 2005 in the United States, and sold out in 2006 to Merck for 10 billion USD.
Bibliography:
BackRub by Ciro Santilli 37 Updated 2025-07-16
This was the original name of Google Search.
One wonders if this name has some influence from the LGBT culture in San Francisco! The sexual innuendo is palpable.
"Back" is of course a reference to "backlinks", since Google Search relies on incoming links (AKA backlinks) to a webpage to determine its importance.

There are unlisted articles, also show them or only show them.