[Tex/LaTex] \star vs. \ast in formulas. Which one to use


When you read a formula aloud you say "r and r-star are related by this formula".
If you write this formula down you normally write an r with a six-handed star, which would actually be an asterisk and not star (with 5 sharp hands) because it's easier to draw by hand.

But what to do when typing this formula in LaTeX? Should I set it as I pronounce it?

r^\star = a r

Or as I write it by hand?

r^\ast = a r

And will \ast always do the same as *?

r^\ast == r^* %???

Is one (\star or \ast) simply wrong (typographically or semantically) or is it just a matter of personal preference?

Best Answer

I think it's just personal preference. In the standard setup * and \ast are the same.

fontmath.ltx has

\DeclareMathSymbol{*}{\mathbin}{symbols}{"03} % \ast

So both pick up character 3 from the symbol font with infix binary operator spacing.

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