I am typing up a set of notes for the Riemann Stieltjes integral. For reasons beyond the scope of the question, I would like to start with defining the Darboux's integral and then formulate Riemann's definition and show that they are equivalent.
During the intermediate steps, provisionally, I would like to define the Riemann integral, the R-integral. To avoid mixing of symbols, I have in mind a symbol like \oint
but with a R
instead of the circle.
I am not aware of what the TeX code for the symbol would be.
Any help would be appreciated.
Best Answer
You may try with the following code:
The absolute value is only for demonstration purpose.
The main problem here is to adapt the R to the various formula styles, so we use
\mathchoice
. With\mathrlap
we can build a zero width box that will not contribute to the width of the formula. Since\int
is an operator, we put this zero width formula into a\mathop
, then\!
is used to remove the space that TeX inserts between two consecutive Operator atoms.Next we define
\pushR
, that's simply a space in display style, followed by a normal size R. In text and lower styles we simply put a reduced size R. Probably the result will not be nice in\scriptscriptstyle
, but it doesn't seem so important.The same idea can be used for the principal value integral: