What Paragraphs and Line Breaks are valid RSS formatting?

开发者_开发问答What html formatting for paragraphs, line breaks, lists, etc are valid in an RSS feed? Im pretty sure divs aren't allowed, but what about ul and li?

I know the theory is that the RSS readers will style the content and you shouldn't go overboard styling it yourself, but what about headings, paragraphs, lists, etc?

Thanks