R help - Mar 2017 - ! in expression(!abc) that produces !(abc).

Hi there,

I happened to find the expression(!abc) produces !(abc) when I used 
plotmath in a text annotation. Here is the mini-example.

 > plot(1, type = "n")
 > text(1,1, expression(!abc))

I don't find "!" in plotmath document.

By the way, how to reduce the space between two adjacent strings, 
something opposite to "~~". I mean, to get a space that is narrower
than
"~" but wider than "*".

Best,
Jinsong