[Tex/LaTex] Decreasing space between subsubsections

document-classeslncssectioningspacing

I use the LNCS document style for a paper. However, I find the spacing between subsubsections (ca 2 lines) very generous and would like to decrease it. How can I do this? (Note: I am not required to adhere to the LNCS formatting rules, so hacking this is okay.)

%% LyX 2.0.5.1 created this file.  For more info, see http://www.lyx.org/.
%% Do not edit unless you really know what you are doing.
\documentclass[10pt,english]{llncs}
\begin{document}
\section{Section A}
\subsubsection{First.}
Lorem ipsum.
% TODO: decrease spacing here
\subsubsection{Second.}
Lorem ipsum.
\end{document}


The space above \subsubsection is similar to that above a \subsection and \section, according to llncs.cls. You need to update the lengths to your liking:

\documentclass{llncs}% http://www.springer.com/computer/lncs?SGWID=0-164-6-793341-0
\begin{document}
\section{A section}
Some text
\subsection{A subsection}
Some text
\subsubsection{A subsubsection}
Some text
\subsubsection{Another subsubsection}
Some text

\bigskip

% Put the block below in your LaTeX preamble
\makeatletter
\renewcommand\subsubsection{\@startsection{subsubsection}{3}{\z@}%
{-8\p@ \@plus -4\p@ \@minus -4\p@}% Formerly -18\p@ \@plus -4\p@ \@minus -4\p@
{-0.5em \@plus -0.22em \@minus -0.1em}%
{\normalfont\normalsize\bfseries\boldmath}}
\makeatother

\section{A section}
Some text
\subsection{A subsection}
Some text
\subsubsection{A subsubsection}
Some text
\subsubsection{Another subsubsection}
Some text
\end{document}


The change was made to the arguments of \@startsection, which is called by \subsubsection (and most other sectioning macros). Specifically, the fourth and fifth argument deal with the space before and after the sectioning command. If it's negative (as is the case with \subsubsection), a run-in title is produced, otherwise it is set as a display. For more on the actual meaning/usage, see Where can I find help files or documentation for commands like \@startsection for LaTeX?