I would like something like this amsthm: \newtheoremstyle, headspace, \mbox{}, and lists but also with an indent after the new line, as if I wrote ~ and pressed enter twice. Ideally without ntheorem. I tried
\newtheoremstyle{break} % follow `plain` defaults but change HEADSPACE.
{\topsep} % ABOVESPACE
{\topsep} % BELOWSPACE
{\itshape} % BODYFONT
{0pt} % INDENT (empty value is the same as 0pt)
{\bfseries} % HEADFONT
{.} % HEADPUNCT
{\linebreak} % HEADSPACE. `plain` default: {5pt plus 1pt minus 1pt}
{} % CUSTOM-HEAD-SPEC
but this gives a weird error about a number missing. A sub question is what LaTeX command gives the same result as pressing enter twice?
\newlineinstead of\linebreakfor the next-to-last argument; that's what is generally recommended, but i don't have time to investigate why. – barbara beeton Aug 28 '17 at 13:46\paris the (la)tex equivalent to a blank line. an alternate form (essentially a primitive, without all the latex addenda) is\endgraf; this is usable in situations where\paror a blank line are not "accepted". – barbara beeton Aug 28 '17 at 15:08\newtheoremstyledefinition that i'm aware of, except possibly in the last, "custom", argument. but even there, it's questionable. there is a "break" theorem style defined in theamsthmusers guide, although it doesn't indent the next line. it does use\newline. i will experiment. – barbara beeton Aug 28 '17 at 21:00