Intuitive definition: real group of rotations + reflections.
Mathematical definition that most directly represents this: the orthogonal group is the group of all matrices that preserve the dot product.
Group of the unitary matrices.
Complex analogue of the orthogonal group.
One notable difference from the orthogonal group however is that the unitary group is connected "because" its determinant is not fixed to two disconnected values 1/-1, but rather goes around in a continuous unit circle. is the unit circle.
Seems to be a GNU Binutils extension
In this project Ciro Santilli extracted (almost) all Git commit emails from GitHub with Google BigQuery! The repo was later taken down by GitHub. Newbs, censoring publicly available data!
Ciro also created a beautifully named variant with one email per commit: github.com/cirosantilli/imagine-all-the-people. True art. It also had the effect of breaking this "what's my first commit tracker": twitter.com/NachoSoto/status/1761873362706698469
GitHub Archive query showing hashed emails
. It was Ciro Santilli that made them hash the emails. They weren't hashed before he published the emails publicly.
All GitHub Commit Emails repo before takedown
. Screenshot from archive.is.Looking for formats that:
- are human readable plaintext files
- can be converted/played as MIDI
- can be converted to sheet music PDFs
- supports basic guitar effects (bends and slides)
Disclaimer: closed source vendors tend to be highly secretive, solving small issues without any reply, so I use my best judgement given the lack of feedback.
Something analogous to a group isomorphism, but that preserves whatever properties the given algebraic object has. E.g. for a field, we also have to preserve multiplication in addition to addition.
Other common examples include isomorphisms of vector spaces and field. But since both of those two are much simpler than groups in classification, as they are both determined by number of elements/dimension alone, see:we tend to not talk about isomorphisms so much in those contexts.
Missileers by BBC (2000)
Source. Documentary about American ICBM crews working on the Francis. E. Warren Air Force Base. Wiki mentions that there are 3 main sites in the USA, and plainshumanities.unl.edu/encyclopedia/doc/egp.ii.042 suggests all/most of them are in the Great Plains area. They operate a Minuteman system, which as of 2021 is the only nuclear ICBM system in the USA.
Good documentary, shows well the day-to-day life of the operator, including outside of the work site.
- youtu.be/w1tMx27Q4O0?t=1390 they drive 100 miles to get to work. They do 8 alerts per month.
- youtu.be/w1tMx27Q4O0?t=1473 the actual missiles are a few miles away from the control center, scattered in a few different locations
- youtu.be/w1tMx27Q4O0?t=1619 they have a television in there at least. Presumably a pre-recorded selection.
This was an intermediate step between the nuclear chain reaction prototype Chicago Pile-1 and the full blown plutonium mass production at Hanford site. Located in the Oak Ridge National Laboratory.
Exterior of the X-10 Graphite Reactor in 1950
. Source. 
Workers loading Uranium into the X-10 Graphite Reactor with a rod
. Source. 
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