Take the 2-minute tour ×
Mathematica Stack Exchange is a question and answer site for users of Mathematica. It's 100% free, no registration required.

In the non-printing characters documentation, I see two named characters that are largely undocumented: \[InvisiblePrefixScriptBase] and \[InvisiblePostfixScriptBase].

Interestingly, they have input aliases defined: [Esc]i-[Esc] and [Esc]-i[Esc].

What are they used for?

share|improve this question
2  
Related (possible dupe): mathematica.stackexchange.com/q/1/5 I'd say that they're mostly for typesetting purposes and for finer control of the placements and positioning of subscripts/superscripts. You might probably use one of these when you need a subscript/superscript that's not attached to any symbol. –  rm -rf Dec 6 '12 at 7:20
4  
Two examples of the first one are (1) TraditionalForm[Hypergeometric2F1[a, b, c, d]], and (2) this Q/A where it is used to typset $_{n}C_{r}$ –  kguler Dec 6 '12 at 7:26
2  
@kguler: So it seems like the Prefix one is meant as an invisible base character for sub-/superscripts that are typeset before the conceptual base character. But the Postfix one is still a mystery. –  Mechanical snail Dec 6 '12 at 9:53
    
I have not come across any usage examples of \[InvisiblePostfixScriptBase] -- who knows? Maybe for right-to-left scripts it works similar to the Prefix one? –  kguler Dec 6 '12 at 11:32
3  
I use \[InvisiblePostfixScriptBase] to emulate the spaces and alignments in some tensor notions. In LaTeX it's usually done by \phantom command. Compare RowBox[{SubscriptBox["F","a"],SubsuperscriptBox["\[InvisiblePostfixScriptBase]"‌​,"b","c"]}]//DisplayForm to LaTeX code F_{ab}^{\phantom{a}c}. –  Silvia Dec 6 '12 at 12:07

1 Answer 1

As the comments to OP described, those invisible marks are usually used as placeholder / anchor for typesetting.

For example, we can use \[InvisiblePostfixScriptBase] to emulate the spaces and alignments in some tensor notions. In LaTeX it's usually done by the \phantom command: Compare RowBox[{SubscriptBox["F", "a"],SubsuperscriptBox["\[InvisiblePostfixScriptBase]"‌, "b", "c"]}] // DisplayForm to LaTeX code F_{ab}^{ \phantom{a} c }.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.