12
votes
4answers
1k views

Notation in Frege's Grundgesetze der Arithmetik: The U with a flourish

In the Grundgesetze der Arithmetik, Frege used a number of strange characters for notation. I would be most interested to know anything about the typography (origin, usage and so on) of the strange U ...
20
votes
1answer
1k views

Community experiences writing Lamport's structured proofs

About two years ago, I came across this paper by Lamport http://research.microsoft.com/en-us/um/people/lamport/pubs/lamport-how-to-write.pdf on writing proofs hierarchically. It changed how I wrote ...
1
vote
5answers
3k views

What is the difference between the biconditional iff. and equality = ?

Hello, I've been used to writing logical transformations using equality, but the other day it struck me that perhaps I should be using the biconditional $\iff$? So my question is: What is the ...