Git remote communcation Updated +Created
Git tips / How to visualize the commit tree Updated +Created
Generate a minimal test repo. You should get in the habit of doing this to test stuff out.
#!/usr/bin/env bash

mkdir git-tips
cd git-tips
git init

for i in 1 2 3 4 5; do
  echo $i > f
  git add f
  git commit -m $i
done

git checkout HEAD~2
git checkout -b my-feature

for i in 6 7; do
  echo $i > f
  git add f
  git commit -m $i
done
Git tips / It's not a tree, it's actually a DAG Updated +Created
But not every directed acyclic graph is a tree.
Example of a tree (and therefore also a DAG):
5
|
4 7
| |
3 6
|/
2
|
1
Convention in this presentation: arrows implicitly point up, just like in a git log, i.e.:
  • 1 is parent of 2
  • 2 is parent of 3 and 6
  • 3 is parent of 4
and so on.
Example of a DAG that is not a tree:
7
|\
4 6
| |
3 5
|/
2
|
1
This is not a tree because there are two ways to reach 7:
But we often say "tree" intead of "DAG" in the context of Git because DAG sounds ugly.
Example of a graph that is not a DAG:
6
^
|
3->4
^  |
|  v
2<-5
^
|
1
This one is not acyclic because there is a cycle 2, 3, 4, 5, 2.
Git tips / Oh, but there are 2 trees: local and remote Updated +Created
Oh but there are usually 2 trees: local and remote.
So you also have to learn how to observe and modify and sync with the remote tree!
But basically:
git fetch
to update the remote tree. And then you can use it exactly like any other branch, except you prefix them with the remote (usually origin/*), e.g.:
  • origin/master is the latest fetch of the remote version of master
  • origin/my-feature is the latest fetch of the remote version of my-feature
libgit2 Updated +Created
Nuclear isomer Updated +Created
Period (physics) Updated +Created
Permanent brain Updated +Created
Bitcoin script Updated +Created
Covariance Updated +Created
Generally means that he form of the equation does not change if we transform .
This is generally what we want from the laws of physics.
E.g. a Galilean transformation generally changes the exact values of coordinates, but not the form of the laws of physics themselves.
Lorentz covariance is the main context under which the word "covariant" appears, because we really don't want the form of the equations to change under Lorentz transforms, and "covariance" is often used as a synonym of "Lorentz covariance".
TODO some sources distinguish "invariant" from "covariant": invariant vs covariant.
Dots in Gmail address Updated +Created
This allows you to create multiple non-anonymous accounts on any website that doesn't account for it, as this is not part of the email protocols in general.
Endohedral fullerene Updated +Created
Financial crisis of 2007-2008 Updated +Created
Gauge field Updated +Created
A random field you add to make something transform locally the way you want. See e.g.: Video "Deriving the qED Lagrangian by Dietterich Labs (2018)".
General-purpose computing on graphics processing units Updated +Created
Girdler sulfide process Updated +Created
Git tips / Merge conflicts Updated +Created
Google Books Updated +Created
They scanned a bunch of books, and then allowed search results to hit them. They then only show a small context around the hit to avoid copyright infringement.
Bibliography:

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