# 816: Applied Math

 Applied Math Title text: Dear Reader: Enclosed is a check for ninety-eight cents. Using your work, I have proven that this equals the amount you requested.

## Explanation

Donald Knuth is a computer scientist that has written several computer science textbooks and he offers rewards for anyone finding errors in his publications. The first error found in each book is worth \$2.56. Other errors and suggestions are worth less than \$2.56, but a check is still sent out if Dr. Knuth finds them to be reasonable.

In this comic, Megan uses a proof to invalidate logic itself. And then, she writes a letter to Dr. Knuth to collect her money for the 1,317,408 errors in The Art of Computer Programming at \$2.56 each.

In the title text is the reply from Dr. Knuth in which he uses Megan's logic disproving proof to evaluate her work down to 98 cents.

Megan probably got the address from Black Hat.

## Transcript

[A woman is standing at a whiteboard considering a logical proof.]

Woman #1: Wow. I can't find fault with your proof.

[The woman is still looking at the white board, the frame expands to show a second woman walking away, rubbing her hands together in an evil manner.]

Woman #1: You've show the inconsistency -- and thus the invalidity -- of basic logic itself.

Woman #2: Excellent, on to step two.

[The second woman sits down at a desk and begins to write.]

Dear Dr. Knuth,

[She continues to write.]

I am writing to collect from you the \$3,372,564.45 I am owed for discovering 1,317,408 errors in The Art of Computer Programming...

# Discussion

Where IS the indication that she got the address from Black Hat ?Guru-45 (talk) 10:45, 17 May 2013 (UTC)

She must have derived it via the principle of explosion. 108.162.221.90 19:58, 12 May 2014 (UTC)

Which is a reference to xkcd #704. 108.162.254.56 11:45, 8 June 2015 (UTC)

If you look in the top-right corner, you can see what looks like "ZFC," (Zermelo-Fraenkel Set Theory with the Axiom of Choice), which is a a dozen or so axioms that all of mathematics is built upon. Because of Godel's Incompleteness Theorems, it is impossible to prove that ZFC contains no contradictions (unless it actually does contain contradictions). If Megan proved the inconsistency of logic, she certainly could show as a corrollary the inconsistency of ZFC, and therefore all of mathematics. Even statements like 2+2=4 could be proven false. String userName = new String(); (talk) 20:20, 7 May 2015 (UTC)