1
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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 ...
4
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2answers
1k views

Why are the Dynkin diagrams E6, E7 and E8 always drawn the way they are drawn?

The Dynkin diagrams of type ADE are ubiquitous in mathematics as solutions of various classification problems. The diagram E6 is usually drawn by five dots in a row with a sixth dot above the third, ...