# How to write special set notation by hand?

Does anyone know a good resource (preferably pictures) that illustrates a conventional way to write the special sets symbols, i.e. $\mathbb{N,Z,Q,R,C}$ etc., by hand?

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In my experience, you kinda just make it up. I don't know of a 'conventional' way. – smackcrane May 31 '12 at 14:38
Just for the fun of it, here is blackboard bold in my terrible handwriting. (In addition to it, scanning something written by pen was probably not that good idea.) – Martin Sleziak May 31 '12 at 14:57
@ Martin I like them! – Sean May 31 '12 at 15:02
@Martin : I write them exactly the same! Except that you sketched the $\mathbb C$ very bad. But I use the same technique :P – Patrick Da Silva May 31 '12 at 16:30

I don't think anybody duplicates mathblackboard very exactly. I'll describe what I do.

For $\mathbb{N}$, I draw the left vertical and a diagonal as normal, then I start over drawing another diagonal parallel to the first, then finish the right vertical. I do something similar for $\mathbb{Z}$.

For $\mathbb{R}$ and $\mathbb{H}$ I write an $R$ or $H$ as normal and then just double the left vertical. For $\mathbb{Q}$ and $\mathbb{C}$ I write a $Q$ or $C$ as normal, then add a vertical secant line close to the left side.

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I mostly do the same, except for my $\mathbb{N}$ I double the left vertical (like $\mathbb{R}$ or $\mathbb{H}$) instead of the diagonal. – Willie Wong May 31 '12 at 14:54
@WillieWong I know I used to do that! I didn't realize I stopped. I think my method for doing $\mathbb{Z}$ probably became contagious and changed my $\mathbb{N}$. Anyway, I would like to endorse that as a completely standard thing, too. – rschwieb May 31 '12 at 14:57

Well this is the way I draw them anyway :)

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terrible choice of background color, but I like it ;) – Milosz Wielondek May 31 '12 at 15:21
ahem! Doesn't it just jump out at you :) – Sean May 31 '12 at 15:33
Your $\mathbb{N}$ is “incorrect” in that a capital N in any serif font has the diagonal thickened, not the verticals. In fact, the rule (in Latin alphabet) is that negative slopes are thick, positive ones are thin. Verticals are sometimes thin, sometimes thick. Unique exception: Z. Just look in a newspaper at A, V, X, M, and N. – Lubin May 31 '12 at 15:45
@Lubin: it's a matter of personal choice. The Latin rule is interesting though, never heard of that. – Sean May 31 '12 at 16:56