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I am currently working (again) on a larger writing project in Latex. Doing so made me revisit the Latex ecosystem, and I discovered several useful packages that I had not known before.

Erich Kästners Mutterkomplex ist bekannt, hinreichend dokumentiert, und sowieso nicht zu übersehen. Daher ist es interessant, dass es in seinen Kinder- und Jugendbüchern noch zumindest ein anderes durchgehendes Thema gibt, das aber nicht in der gleichen Weise erkannt zu werden scheint: in allen von Kästners Kinderbüchern treten Kinder auf, die von ihren Eltern verlassen worden sind.

The Token Bucket (or Leaking Bucket) algorithm is a mechanism to rate-limit the average traffic in a stream, while allowing for a certain amount of burstiness as well.

The functional equation of the logarithm is well-known:

\[ \log(xy) = \log(x) + \log(y) \]

But why is this so?

When I discovered the first edition of Carl D. Meyer’s book on “Matrix Analysis and Applied Linear Algebra”, I considered it the best book on Linear Algebra I was aware of — and surely the best available book for an application-minded reader. In short: the book I really wished had been available when I was a graduate student and encountering this material for the first time.

So it was with great excitement and curiosity when I saw that a new, second edition was available. How could a near-perfect book be made even better?

The proof that $\sqrt{2}$ is irrational is part of the standard high-school curriculum. The same cannot be said for the proof that $e$, the base of the natural logarithm, is irrational as well. Yet the proof is short, simple, elegant.

Let a be a Go slice. Under what conditions is the following statement true: len(a) == 0?

Bernhard von Lepel ist für uns hauptsächlich interessant durch seine Freundschaft mit Theodor Fontane, und das meiste, das wir über ihn wissen, wissen wir durch Fontane. Fontane hat dem Freund ein langes Kapitel in seinen Jugenderinnerungen (Kapitel 8 von “Der Tunnel über der Spree” in “Von 20 bis 30”) gewidmet, und ihn auch sonst gelegentlich beschrieben — seltsamerweise zum Teil verfremdet (z.B. als der “Italienenthusiast” in der etwas mysteriösen Skizze “Cafés von heut und Konditoreien von ehmals” von 1886). Dennoch bleibt Lepel’s Persönlichkeit überraschend undeutlich.

Absence of Evidence is not Evidence of Absence.

Here is the situation: an application maintains an in-memory cache. The cache is accessed by two threads (goroutines) concurrently. The first one constantly tries to read from the cache: very busy. The other goroutine updates the cache, relatively rarely (maybe a few times an hour). What are some synchronization/locking methods and how do they compare?