Neues in der Kategorie Short post

In genau -140 Jahren wird Bertrand Russell geboren werden. Darauf hat mich grade DuckDuckGo aufmerksam gemacht. Bekannt ist Russel zum Beispiel für die Russel-Klasse <m>R=\{x|x\not\in x\}</m>, eine Instanz der Russel'schen Antinomie. Naja. Alles Gute.


Source: Wikipedia

Nibbles was a Snake-like game, which was part of MS-Dos, as an example file for QBasic. The name "Nibbles" (probably ?) came from the half-bytes - "nibbles" - since on the terminal, it uses characters that split every terminal character into two parts.

Well, there are a lot of newer Snake-like games out there. However, the special thing about cNibbles is that it is, as the original Nibbles, a pure terminal application.

Normalerweise halte ich nichts von den staatlichen Versuchen, Videospiele zu verteufeln, aber dieses Video (vorsicht, laut dieser Seite nicht geeignet für Kinder unter 12 Jahren) brachte mich zum Lachen, also insbesondere der Teil ganz am Ende.

(Direktlink)

A great article, with interesting references, and as it is about something many people do not seem to understand, worth reading:

> The abstraction-optimization tradeoff

... gab letzens eine Mitarbeiterin der geliebten TU-Mensa von sich, vermutlich unüberlegt und genervt vom Riechverhalten meines Kommilitonen.

Meinen Kommentar, dies sei im Allgemeinen ein schlechtes Motto für eine Küche, hat sie offenbar nicht verstanden.

In der Bürgerversammlung Laim (Stadtteil 25 in München) gab es einen lustigen Kommentar von Ude (aktueller Müncher Oberbürgermeister, geht in den aktuellen Wahlkampf in Bayern als Bewerber auf den Posten des Ministerpräsidenten). Er erläuterte erst, daß er eine bestimmte Regelung nicht ändern kann (wozu er aufgefordert wurde) weil das Landesrecht ist. Dazu sagte er in etwa "Den Münchner Oberbürgermeister aufzufordern er möge bayrisches Landesrecht ändern ist zumindestens ... verfrüht."

... an den wichtigen Stellen wird sie nur von Nieten zusammengehalten.

(via)

I gave a short talk about the irrefutability of the axiom of choice from ZF for some younger students, in the scope of a seminar of the best mathematics club of the multiverse.

I wanted to create a script, and instead of putting up a LaTeX-document which will then collect dust in one of my backup directories, I thought I'd write a short series of postings giving a script for this talk. Unfortunately, it is rather complicated, and I am not sure whether I can recommend that.

The talk was in German, these posts will be in English, though. I will separate them in parts, and will publish the parts delayed, as they will be very long. I hope that everyone interested in it will enjoy it.

In the end, the talk was a lot shorter and I have left out a lot of stuff. It is impossible to put all of that matter into a two hours talk for people not familiar with logic.

It is based on my lecture notes for the lecture "Models of Set Theory" given by Donder (whom I thank for giving his permission to do so), and the book "Set Theory" by Kunen, and "Einführung in die Mengenlehre" by Oliver Deiser.

What I want to do is give an ontological introduction to the topic, as I think there is no such thing yet. That is why I do not give the proof for the independence of AC, but only for the irrefutability.

This is not a scientific paper!

This time I will only publish an outline, which I will fill with hyperlinks as soon as I post them (so this post will be updated until all parts are published):

Part 1 will be about the basic logical background needed for this:

• Formulae
• First-Order Theories
  
• Interpretations and Models
• A Simple Independence Proof
  

Part 2 will be about ZF:

• Classes
  
• Axioms of ZF
• The Axiom of Choice
  
• Well-Orderings, Ordinals and Transfinite Induction

Part 3 will be about inner models:

• The V-Hierarchy
• Inner Models
  

Part 4 will then contain the actual proof:

• The Classes OD and HOD
• HOD <m>\models</m> AC

It is likely that I made some mistakes, so if you see one, feel free to send comments.

According to Gulli News, Windows 8 will not shut down completely, but keep a memory image which is then loaded to RAM, to improve the speed of the startup. This reminds me of a quote regarding Smalltalk:

I always show this, when asked by C/C++ programmers, as a typing in of "Hello, World!," preferably into an empty Transcript pane. And then I save the image. Loading the program subsequently brings up: "Hello, World!" Individuals will quibble over this relentlessly, saying, "It's not the same!" I can only agree that it's not the same, but that was my point about the languages and their environments in the first place.

Has a bit of Smalltalk's philosophy reached the practical world?