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My Sandbox

Now filled with eco-friendly locally gathered sand.

User:Dfeuer/To Do

A partial list of my favorite composers, conductors, and performers

Pēteris Vasks

Samuel Barber

Gustav Holst

Benjamin Britten

Eric Whitacre

Modest Mussorgsky

Maurice Ravel

Paul Simon

Leonard Bernstein

Joan Baez

Hila Plitmann

Frank Sinatra


The Beatles

Simon and Garfunkel

Proof that $0 + 1 = 0$

Using Von Neumann Natural Numbers:

$0 = \varnothing$

Let $f: \N \to \N$ be the successor mapping. That is, let $f(x) = x^+$.

Then $f(0)$ is the image of the empty set under $f$, so $f(0) = f(\varnothing) = \varnothing = 0$.

Thus $0^+ = 0$.

So by the definition of addition, $0 + 1 = 0$.


What is math?

Mathematics is a family of creative games. The players, called mathematicians, can score points in the game by making any of several different plays. The primary plays are proving theorems and finding counterexamples to conjectures. Secondary plays include creating new subgames or game variants and forming conjectures that drive game-play.

Pages I am working on or intend to work on

Just to keep track.


User:Dfeuer/Topological Field

Etymological Dictionary of PW User Names

  • Dfeuer < D. Feuer < Feuerwerger, a Germanic name < feuer (fire) + werker (worker)
  • prime.mover < prime (original) + mover, from the notion that all actions were ultimately initiated by God. Cf. first cause (although, given the paltry level of politico-social sophistication of the user in question, coupled with his egregious lack of respect for and ignorance of history, classics and education in general, more likely stolen from the title of a song by the über-macho goth/punk/sleaze band Zodiac Mindwarp and the Love Reaction)
  • Lord_Farin < Farin, a character in the Lord of the Rings lore.
  • Anghel < "messenger", a Romanian name that can be used both as a first name and a surname.

User:Dfeuer/Wadler's Law

In any language design, the total time spent discussing a feature in this list is proportional to two raised to the power of its position.

0. Semantics
1. Syntax
2. Lexical syntax
3. Lexical syntax of comments

Source: Haskell Wiki

On $\mathsf{Pr} \infty \mathsf{fWiki}$, if you look at arguments about how things should be done, it looks something like

0. Proof techniques
1. Definitions
3. Variable names
4. Page names
5. $\LaTeX$ source style
6. Complaining about it