C!

The C! is a way to reward a noder for submitting a particularly good writeup whether it be factual, humorous or artistic. Basically, a way of saying you appreciated the writeup and wanted to let the author know and give the writeup more attention than it would have had otherwise. By C!'ing someone's writeup you send that writeup to the Cool Archive and possibly even onto the front page. E2 will also reward that user with 10 xp.

You get the power to C! writeups beginning at 4th level. A writeup can accrue any number of C!'s but a user can C! any given writeup only once. Further C!s must be given by other users. For details on C!'s and the rest of the level system see the voting/experience system document.

A nice feature to turn on in your user settings is Cool Man Eddie. He's the shit. He will msg you in the chatterbox everytime somebody C!'s one of your writeups telling you who 'chinged' your work. In user settings click the box by "Tell me when I get cooled."

User settings also lets you enable a "cool safety" so you don't accidentally C! somebody's writeup when you only meant to cast a vote.

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E2 Glossary

In certain mathematician circles, C! is also a shorthand term for "contradiction." The clearest example of its proper usage can be found in a problem involving solving a system of equations.

Suppose that you are given the following system to solve:

(i) x + 4y - z = 4
(ii) 3x - 2y + 5z = 6
(iii) 5x + 6y + 3z = 13

One solution¹ to this system involves eliminating one of the variables and then adding or subtracting the resulting equations. Let us add (iii) with 3*(i).

3*(i) 3x + 12y - 3z = 12
(iii) 5x + 6y + 3z = 13
(iv) 8x + 18y = 25

We would then add 5*(i) to (ii) to garner a second equation without a "z" term.

5*(i) 5x + 20y - 5z = 20
(ii) 3x - 2y + 5z = 6
(v) 8x + 18y = 26

Subtracting (iv) from (v) produces the result 0=1 which immediately implies a contradiction. Namely C!. Therefore, a solution with only contradictory solutions C! has no solutions.

Node what you know.
Node your homework.

¹Other solution methods include but are not limited to the iterative method, back substitution, matrices, and graphs.