[texhax] correct spacing between adjacent quote marks

[P. R. Stanley]

>>>         Paul: The question concerns the correct amount of 
>>> horizontal spacing
>>>between a single quote and a double quote mark. for example,
>>>``\thinspace`bla bla'\thinspace''
>>>`\thinspace``rabit rabit rabit''\thinspace'
>>>or is it
>>
>>\thinspace is a bit too large, IMO.
>
>Of course one can make additional kerning spaces à la \thinspace. I
>usually use two extra positive thin spaces:
>
>\def\fino{\kern 0.1em }
>\def\finito{\kern 0.05em }
>
>(\fino from Spanish ``thin'' and \finito from ``very thin'')
>
>and one negative:
>
>\def\finoneg{\kern -0.1em }
         Paul: Where would you use the negative thin spacing? I'm not 
quite sure of the concept of negative spacing, so any furhter 
clarification would be much appreciated.
Incidentally, the above demos were inspired by Knuth's TeXBook. He 
uses \thinspace between the single and double quote marks but if you 
say the gap is too large then ...