[texhax] Displaying math in the same line

[Soeren D. Schulze]

On 24.05.2011 20:12, Philipp Stephani wrote:
>> \noindent{\bf Pythagoras' Theorem:}
>> %\vskip-24pt
>> $$a^2+b^2=c^2$$
>> \bye
 >>
 >> [...]
>
> Maybe just
>
> \noindent\rlap{\bf Pythagoras' Theorem:}\hfil$a^2+b^2=c^2$\hfil\par
> \bye

Thanks, that almost what I'm looking for.
But what if I make it more complex?  Say I want:
$$\langle v,w \rangle := \sum_{i=1}^n v_i\cdot w_i$$

What I want to do is to format the displayed equation as if the 
introductory text hadn't been there.

Is it possible to clean up the following code to do something useful?

hello world!\par
\vbox to 0pt
{\noindent{\bf Dot Product:}}
\vbox{$$\langle v,w \rangle := \sum_{i=1}^n v_i\cdot w_i$$}
bye world
\bye

Problems:
1. The first vbox causes an extra vertical space.
2. The last vbox starts a new paragraph.
3. It's incompatible with, say, LaTeX macros.

BTW: Do you consider this a typographically legitimate question, or am I 
completely on the wrong track?


Thanks,

Sören