Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

I've wished for this a time or two. Let's see: > < ⇒ Δ π Σ ≅ ∠∫ ≥ ≤

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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

Hmm...guess not. But, I think it would be much easier, or at least faster (for me, anyway) to use these than to copy and paste from the top.

Do we have [sup]sup[/sup] and [sub]sub[/sub] tags?

El que pega primero pega dos veces.

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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

Guess not. Also a good suggestion.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,559

Good suggestions ... I will clear a bit of time and get my head stuck into the forum software and see what can be done.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,559

After a bit of research, I think I can use "smiley" style for these special characters.

It would be something like typing **Δ** to produce Δ

(BTW We do have a functioning "math" tag that uses LaTeX code, but for a lot of things these characters work well.)

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

Ah yes...LaTeX...that's on my to learn list.

Couldn't you just zap the & literalizer? What I mean is, when I type Δ, the forum software converts it to Δ.

Well, there must be some benefit to the & literalizer. Maybe you could just check for a ; within 10 chars or so to decide whither to literalize or not.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,559

That is an idea, but I prefer to allow/disallow stuff specifically so that hackers can't take advantage.

I can't think how replacing :blah with &blah could be used for hacking, but that could be because I'm not a hacker.

At the moment I have about 60 symbols I want to apply this "smiley" thing to, and I have done some timing, and it can do the find/replace in under a millisecond. I think a millisecond overhead per post is OK.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,559

OK, here we are, I have made the changes. Hopefully I haven't made anyhing else go crazy, but I am sure someone will let me know!

To make any of these work, put a ":" in front of the text.

alpha=α and=∧ ang=∠ asymp=≈ beta=β bull=• cap=∩ cong=≅ cup=∪ deg=° Delta=Δ delta=δ divide=÷ empty=∅ epsilon=ε equiv=≡ exist=∃ fnof=ƒ forall=∀ frac12=½ frac14=¼ frac34=¾ gamma=γ ge=≥ harr=↔ hArr=⇔ infin=∞ int=∫ isin=∈ lambda=λ laquo=« larr=← lArr=⇐ le=≤ mu=μ nabla=∇ ne=≠ ni=∋ notin=∉ nsub=⊄ omega=ω oplus=⊕ otimes=⊗ part=∂ Phi=Φ pi=π plusmn=± prime=′ Prime=″ prod=∏ prop=∝ radic=√ raquo=» rarr=→ rArr=⇒ rho=ρ Sigma=Σ sigma=σ sim=∼ sube=⊆ sub=⊂ sum=∑ sup1=¹ sup2=² sup3=³ supe=⊇ sup=⊃ tau=τ there4=∴ theta=θ times=× xi=ξ zeta=ζ

I also did a trick with some of them, for example "pi" looks a lot more like pi really does (π vs π) because I used a different font for it.

Thanks ryos for the great idea.

Example usage:

π ≅ 22 ÷ 7

`:pi :cong 22 :divide 7`

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**justlookingforthemoment****Moderator**- Registered: 2005-05-26
- Posts: 2,161

⊂ ° ° ζ !

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,559

Still laughing ... !!!

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

What does ≅ mean? Or is it supposed to be something other than a box?

π ≈ 22/7 works for me, although 355/133 is a much better estimate.

Anyway, it's a very useful addition. It's much better than just copying and pasting from the top, and we have more symbols to choose from too.

Why did the vector cross the road?

It wanted to be normal.

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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

Awesome, that was really quick!

∀ ∠ ∃ θ

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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

Do we need to separate them with spaces?

ΔγΦ

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