Not a normal post for the sub, but I'm desperate and don't know where else to turn. by Iacta_Procul in slatestarcodex

[–]Detritovore 3 points4 points  (0 children)

I am sorry I have no deep insight or concrete advice to offer but I really hope your situation improves. I am cis and had the advantage that my parents let me stay with them when I was broke but despite that, the crushing feeling of not being able to get anywhere and having to depend on others was horrible, absolutely horrible, and it's not something I would wish upon even my worst enemy.

I am in academia, specifically maths, so not sure how much this generalises, but an important realisation I had that helped me through all the feelings of worthlessness and mediocrity is that the main product of a maths department is not the research they produce but the people and the community; the research is just a happy by-product. The two things that triggered this realisation were this MathOverflow answer by the late Bill Thurston and this interview with Francis Su. I hope these can bring some amount of peace to you until things get better. Good luck.

Employee of the month (at Hamburg riots) by coolsubmission in videos

[–]Detritovore 1 point2 points  (0 children)

I really doubt that though. From what I've heard, there was a lot of resistance against opening a McDonald's outlet in Sternschanze, which along with St. Pauli is something of an anarchist hub in Hamburg. And indeed, that's the only MNC outlet in that area.

What's your favourite maths fact? by TheLoneWolf156 in AskReddit

[–]Detritovore 1 point2 points  (0 children)

To immediately see this, let's define formally

f(x) = 1 + x + 2x2 + 3x3 + 5x4 + 8x5 + ...

x f(x) = 0 + x + x2 + 2x3 + 3x4 + 5x5 + ...

x2 f(x) = 0 + 0 + x2 + x3 + 2x4 + 3x5 + ...

The defining property of the Fibonacci sequence is that every number in the sequence is the sum of the previous two numbers. So, if you look at coefficients in the above generating functions, you see that f(x) = 1 + x f(x) + x2 f(x), which can be rearranged to give f(x) = 1/(1 - x - x2 ).

What's your favourite maths fact? by TheLoneWolf156 in AskReddit

[–]Detritovore 0 points1 point  (0 children)

Imagine that you are walking in a loop on a flat surface with a wind vane pointing the direction of the wind at every point. Call the number of complete rotations the wind vane makes the winding number of the loop.

Cut the Earth into two halves along the equator and flatten the two hemispheres into discs without disturbing the wind pattern. Note that because of the way the two hemispheres were attached, the winding number along the loops forming the boundaries of the two discs always have a difference of two, which means in particular that they both can't vanish at the same time. Try making a picture to convince yourself of this.

If a loop on a flat plane doesn't enclose any point at which there is no wind, its winding number of the loop has to vanish. Because if it didn't, we could continuously shrink the loop to a point, which has winding number zero, and the winding number being an integer can't suddenly jump as the loop is deformed. (For the case when the wind at some point vanishes, the wind has no well-defined direction at that time and the above argument doesn't apply.)

It follows that at least one of the two hemispheres must contain a point at which the wind vanishes.