Titlesec and ACM conference format: How to get proper capitalization of sections

The ACM conference format requires that the first three sections "Catagories and Subject Descriptors", "General Terms" and "Keywords" be special sections with lowercase titles. All other sections should be uppercase. In the sig-alternate document template provided here this special capitalization scheme is implemented by defining the commands \catagories, \terms and \keywords.

\def\keywords{\if@twocolumn
\section*{Keywords}
\else \small
\quotation
\fi}


As soon as I include the titlesec package in my paper, all section titles become lowercase. I can make all section titles uppercase with the following command: \titleformat{\section}{\secfnt\uppercase}{\thesection}{1em}{} where \secfnt is a special section font defined in the ACM template. All sections become uppercase because the definitions of \keywords etc. are just specially defined sections (see above code block).

My question is does anyone know how to implement the special capitalization scheme required by ACM while still useing the tilesec package? Or maybe an alternative way to reduce spaceing between sections without useing tilesec? For refference the way section capitialization is implemented in the .cls template file is:

\def\section{%
\@startsection{section}{1}{\z@}{-10\p@ \@plus -4\p@ \@minus -2\p@}% GM
}

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If you are submitting a paper to a conference that requires that class, just do as they want and don't add titlesec. –  egreg Oct 6 '12 at 8:14
Yes but if it is possible to solve this then titlesec can save me alot of space. Do you know an alternative way to change the spaceing between sections? –  Caleb Serafy Oct 7 '12 at 5:13

The definition you report states that the spacing before the section title is 10pt, extendable to 14pt and shrinkable to 8pt (the fourth argument to \@startsection) and that the spacing after the title is 4pt (fifth argument).

The negative values in -10\p@ \@plus -4\p@ \@minus -2\p@ tell LaTeX that the following paragraph should not be indented; the positive value in the fifth argument tells that this sectioning level is "displayed" rather than "run in".

So if you want no space after the section title and to reduce the space above you can do something like

\makeatletter
\def\section{%
\@startsection{section}{1}{\z@}%
{-6\p@ \@plus -2\p@ \@minus -1\p@}%Caleb Serafy
{1sp}%Caleb Serafy
}
\makeatother


Notice that I didn't say 0pt (or the equivalent 0\p@ or \z@ in a \makeatletter regime) for the fifth argument, but 1sp (the minumum positive length, which is unnoticeable by the naked eye). I've marked the modifications with your name, as did GM when changed the setup in the style sheet.

However, I don't think that the conference organizers will be happy about this, since they provide a stylesheet just to ensure uniform appearance of the papers.

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