Separating Paragraphs: Indentation vs Vertical Space

[Bruce Pourciau]

At various spots within a document where paragraphs are separated with  
indentation, I often have claims, propositions, laws, etc, which I  
would like formatted flush left with some vertical space before and  
after. For various reasons, I wish to avoid using the AMS theorem,  
lemma, etc, environments to do this. I've been using soft returns  
(command-return on a Mac) -- two above and two below -- but this  
method results in too much vertical space around the assertion. I  
could also use normal paragraphing, where I insert a \noindent and  
adjust the vertical spacing above and below, but this seems  
cumbersome. Any easier, more systematic methods for this?

Bruce