hi davide, i'm copying the code which define the \probmax function.

but this function is a mathematic one, it's made up to write better mathematic problem in a particular form....so it's a mathematic command, not other latex commands.

this is the code:

%

% PREAMBLE.TEX

% written by RDL

% version 2.0

% last modified October 8, 1998

%

\def\fileversion{2.1}

\def\filedate{1998/11/15}

\wlog{LaTeX `preamble' \fileversion\space<\filedate> (RDL)}

\typeout{LaTeX `preamble' \fileversion\space<\filedate> (RDL)}

\makeatletter

%

% shortcut definition

%

\newcommand{\lineitem}[1]{\item[#1]\mbox{}}

\newcommand{\oneto}[1]{1, \ldots, {#1}}

\newcommand{\dst}{\displaystyle}

\newcommand{\ie}{i.e., }

\newcommand{\POW}{Piece-Of-Work }

\newcommand{\POWs}{Piece-Of-Works }

\newcommand{\RHS}{right--hand-side}

\newcommand{\LHS}{left--hand-side}

%

% roman text in mathmode commands

%

\newcommand{\insmat}[1]{\mathop{\mbox{\rm #1}}} % for mathmode

%(with underlines)

\newcommand{\inmat}[1]{\mbox{\rm {#1}}} % roman text in mathmode

\def\1{{\mathchoice {\roman {1\mskip-4mu l}} {\roman {1\mskip-4mu l}}

{\roman {1\mskip-4.5mu l}} {\roman {1\mskip-5mu l}}}}

%

% common definitions needed

%

\newcommand{\geeq}{ { {{}\atop{>}}\atop{{=}\atop{}}}}

\newcommand{\leeq}{ { {{}\atop{<}}\atop{{=}\atop{}}}}

\newcommand{\infinity}{\infty}

%\newcommand{\ip}[2]{\left\langle #1,#2 \right\rangle}

\newcommand{\ip}[2]{{#1}^T{#2}}

\newcommand{\inv}[1]{#1^{-1}}

\newcommand{\norm}[1]{\left\| #1 \right\|}

\newcommand{\pnorm}[2]{\norm{#1}_#2}

\newcommand{\pop}[1]{P_{#1}}

\newcommand{\ppop}[2]{P_{#2,#1}}

\newcommand{\pproj}[3]{P_{#2,#1}(#3)}

\newcommand{\proj}[2]{\pop{#1}(#2)}

\newcommand{\modulus}[1]{\left| #1 \right|}

\newcommand{\set}[2]{\left\{ #1 \mid #2 \right\}}

\newcommand{\seq}[1]{\left\{ #1 \right\}}

\newcommand{\goes}{\rightarrow}

\newcommand{\nin}{\in\hspace*{-1.8ex}/\hspace*{1.0ex}}

\newcommand{\abs}[1]{\left | #1 \right |}

\newcommand{\der}{\nabla}

\@ifundefined{grad}

{

\newcommand{\grad}{\nabla}

}{}

\newcommand{\half}{\frac{1}{2}}

\newcommand{\intsect}{\bigcap}

\newcommand{\summ}[2]{\sum_{#1}^{#2}}

\newcommand{\union}{\cup}

\newcommand{\define}{:=}

\newcommand{\ldef}{:=}

%\newcommand{\ldef}{\mathrel{\raise.095ex\hbox{:}\mkern-4.2mu=}}

%\newcommand{\ldef}{\stackrel{\mathrm{def}}{=}}

\newcommand{\rdef}{=:}

\newcommand{\msp}{\;\;}

\newcommand{\floor}[1]{\lfloor{#1}\rfloor}

\newcommand{\ceil}[1]{\lceil{#1}\rceil}

\newcommand\refe[1]{(\ref{#1})}

%

% common number system

%

\@ifundefined {flalign}

{

\newcommand{\real}[1]{{\mathrm I\!R}^{#1}}

\def\C{{\mathrm\;\rule{.1em}{1.55ex}\!\!C}}

\def\R{\inmat{\rm I}\!\inmat{\rm R}}

\def\Q{{\mathrm\;\rule{.1em}{1.55ex}\!\!Q}}

\def\Z{{{\mathrm Z}\!\!{\mathrm Z}}}

\def\N{\inmat{\mathrm I}\!\inmat{\mathrm N}}

}

{

\newcommand{\field}[1]{\mathbb #1}

\def\C{\field{C}}

\def\R{\field{R}}

\def\Q{\field{Q}}

\def\Z{\field{Z}}

\def\N{\field{N}}

}

\def\reals{\openR}

\def\integers{\openN}

\def\Fm{\openF^m}

\def\Fn{\openF^n}

\def\Rm{\openR^m}

\def\Rl{\openR^l}

\def\Rn{\openR^n}

\def\Rd{\openR^d}

\def\Rs{\openR^s}

\def\Cs{\openC^s}

\def\Rmn{\openR^{m\times n}}

\def\Rnm{\openR^{n\times m}}

\def\Zm{\openZ^m}

\def\Zn{\openZ^n}

\def\Zd{\openZ^d}

\def\Zs{\openZ^s}

%

% misc

%

\def\setstretch#1{\renewcommand{\baselinestretch}{#1}}

\def\suchthat{\hbox{\mathrm\ s.t.\ }}

\def\cond{\mathop{\mathrm cond}}

\def\vol{\mathop{\mathrm vol}}

\def\dom{\mathop{\mathrm dom}}

\def\ran{\mathop{\mathrm ran}}

\def\tar{\mathop{\mathrm tar}}

\def\jump{\mathop{\mathrm jump}}

\def\for{\mathop{\mathrm for}}

\def\all{\mathop{\mathrm all}}

% note: since \span is a plain TeX operator, use something else here

\def\diam{\mathop{\mathrm diam}}

\def\signum{\mathop{\mathrm signum}}

\def\area{\mathop{\mathrm area}}

\def\const{{\mathrm const}{}}

\def\supp{\mathop{\mathrm supp}}

\def\meas{\mathop{\mathrm meas}}

\def\boldA{{{\bf A}}}

\def\boldB{{{\bf B}}}

\def\boldC{{{\bf C}}}

\def\boldK{{{\bf K}}}

\def\boldL{{{\bf L}}}

\def\boldO{{{\bf O}}}

\def\cA{\mathcal A}

\def\cB{\mathcal B}

\def\cD{\mathcal D}

\def\cF{\mathcal F}

\def\cZ{\mathcal Z}

\def\cN{\mathcal N}

\def\cM{\mathcal M}

\def\cK{\mathcal K}

\def\openA{{{\mathrm A}\kern-.63em{\mathrm A}}}

\def\openB{{{\mathrm I}\kern-.16em {\mathrm B}}}

\def\openC{{\mathrm C\kern-.18cm\vrule width.6pt height 6pt depth-.2pt \kern.18cm}}

\def\openD{{{\mathrm I}\kern-.16em {\mathrm D}}}

\def\openF{{{\mathrm I}\kern-.16em {\mathrm F}}}

\def\openI{{{\mathrm I}\kern-.2em {\mathrm I}}}

\def\openH{{{\mathrm I}\kern-.16em {\mathrm H}}}

\def\openK{{{\mathrm I}\kern-.16em {\mathrm K}}}

\def\openN{{{\mathrm I}\kern-.16em {\mathrm N}}}

\def\openP{{{\mathrm I}\kern-.16em {\mathrm P}}}

\def\openQ{{\mathrm Q\kern-.21cm\vrule width.6pt height 6.2ptdepth-.2pt \kern.21cm}}

\def\openQ{{{\mathrm Q}\kern-.63em {\mathrm Q}}}

\def\openR{{{\mathrm I}\kern-.16em {\mathrm R}}}

\def\openS{{{\mathrm S}\kern-.68em{\mathrm S}}}

\def\openT{{{\mathrm T}\kern-.30em {\mathrm T}}}

\def\openZ{{{\mathrm Z}\kern-.28em{\mathrm Z}}}

\def\sumZ{\sum_{j\in\Zd}}

\def\Iff{\hskip1em\Longleftrightarrow\hskip1em}

\def\iff{\Longleftrightarrow}

\def\Implies{\hskip1em\Longrightarrow\hskip1em}

\def\implies{\Longrightarrow}

\def\Implied{\hskip1em\Longleftarrow\hskip1em}

\def\implied{\Longleftarrow}

\def\ga{\alpha}

\def\gA{{\mathrm A}}

\def\gb{\beta}

\def\gB{{\mathrm B}}

\def\gga{\gamma}

\def\gG{\Gamma}

\def\gd{\delta}

\def\gD{\Delta}

\def\gep{\epsilon}

\def\gz{\zeta}

\def\gZ{{\mathrm Z}}

\def\gth{\theta}

\def\gTh{\Theta}

\def\gk{\kappa}

\def\gl{\lambda}

\def\gL{\Lambda}

\def\gm{\mu}

\def\gM{\mathrm M}

\def\gn{\nu}

\def\gf{\varphi}

\def\gF{\Phi}

\def\gy{\upsilon}

\def\gk{\kappa}

\def\gs{\sigma}

\def\gS{\Sigma}

\def\gt{\tau}

\def\gT{{\mathrm T}}

\def\gr{\varrho}

\def\gR{{\mathrm P}}

\def\Chi{{\mathrm X}}

\def\go{\omega}

\def\gO{\Omega}

%

% Shortcut for commands

%

\newcommand{\SingleSpace}{\edef\baselinestretch{0.9}\Large\normalsize}

\newcommand{\DoubleSpace}{\edef\baselinestretch{1.4}\Large\normalsize}

\newcommand{\Heading}[1]{\par\noindent{\bf#1}\nopagebreak\ }

\newcommand{\Tail}[1]{\nopagebreak\par\noindent{\bf#1}}

\newcommand{\QED}{\vrule height 1.4ex width 1.0ex depth -.1ex\ } % square box

\@ifundefined{flalign}

{

}

{

\renewcommand{\atop}[2]

{\genfrac{}{}{0pt}{}{#1}{#2} }

}

%

% convex analysis definitions

%

\@ifundefined{flalign}

{

\newcommand{\Aff}{\insmat{aff}}

\newcommand{\Conv}{\insmat{conv}}

\newcommand{\Diag}{\insmat{diag}}

\newcommand{\Eff}{\insmat{eff}}

\newcommand{\Paral}{\insmat{par}}

\newcommand{\Intr}{\insmat{int}}

\newcommand{\Ri}{\insmat{ri}}

\newcommand{\Cl}{\insmat{cl}}

\newcommand{\Co}{\insmat{co}}

\newcommand{\Bdry}{\insmat{bdry} }

\newcommand{\Cone}{\insmat{cone} }

\newcommand{\Rec}{\insmat{rec} }

\newcommand{\Lin}{\insmat{lin} }

\newcommand{\EEP}{\insmat{EP} }

}

{

\RequirePackage{amsgen}

\DeclareMathOperator*{\Aff}{aff}

\DeclareMathOperator*{\Conv}{conv}

\DeclareMathOperator*{\Diag}{diag}

\DeclareMathOperator*{\Eff}{eff}

\DeclareMathOperator*{\Paral}{par}

\DeclareMathOperator*{\Intr}{int}

\DeclareMathOperator*{\Ri}{ri}

\DeclareMathOperator*{\Cl}{cl}

\DeclareMathOperator*{\Co}{co}

\DeclareMathOperator*{\Bdry}{bdry}

\DeclareMathOperator*{\Cone}{cone}

\DeclareMathOperator*{\Rec}{rec}

\DeclareMathOperator*{\Lin}{lin}

\DeclareMathOperator*{\EEP}{EP}

}

\newcommand{\aff}[1]{\Aff #1}

\@ifundefined{diag}

{

\newcommand{\diag}[1]{\Diag\left (#1 \right )}

}{}

\newcommand{\eff}[1]{\Eff #1}

\newcommand{\conv}[1]{\Conv #1}

\newcommand{\paral}[1]{\Paral #1}

\newcommand{\intr}[1]{\Intr #1}

\newcommand{\ri}[1]{\Ri #1}

\newcommand{\cl}[1]{\Cl #1}

\newcommand{\co}[1]{\Co\left( #1 \right)}

\newcommand{\clco}[1]{\cl{\co{#1}}}

\newcommand{\bdry}[1]{\Bdry #1}

\newcommand{\cone}[1]{\Cone #1}

\newcommand{\rec}[1]{\Rec #1}

\newcommand{\lin}[1]{\Lin #1}

\newcommand{\EP}[1]{\EEP\left (#1 \right )}

\newcommand{\barrier}[1]{\insmat{bar} #1}

\newcommand{\conj}[1]{#1^*}

\newcommand{\indicator}[2]{\psi(#1 \mid #2)}

\newcommand{\indfn}[1]{\indicator{\cdot}{#1}}

\newcommand{\support}[2]{\conj{\psi}(#1 \mid #2)}

\newcommand{\suppfn}[1]{\support{\cdot{#1}}}

\newcommand{\dist}[2]{\insmat{dist}(#1 \mid #2)}

\newcommand{\distfn}[1]{\dist{\cdot}{#1}}

\newcommand{\ncone}[2]{N(#1 \mid #2)}

\newcommand{\tcone}[2]{T(#1 \mid #2)}

\newcommand{\pcone}[1]{{#1}^\circ}

\newcommand{\polar}[1]{{#1}^\circ}

\newcommand{\epi}[1]{\insmat{epi} #1}

\newcommand{\epiwrt}[2]{\inmat{epi}_{#2}#1 }

%

% numerical analysis definition

%

\@ifundefined{flalign}

{

\def\Rank{\mathop{\mathrm rank}}

\def\SSpan{\mathop{\mathrm span}}

\def\NNull{\mathop{\mathrm null}}

}

{

\RequirePackage{amsgen}

\DeclareMathOperator*{\Rank}{rank}

\DeclareMathOperator*{\SSpan}{span}

\DeclareMathOperator*{\NNull}{null}

}

\@ifundefined{rank}

{

\newcommand{\rank}[1]{\Rank #1}

}{}

\newcommand{\Span}[1]{\SSpan #1}

\newcommand{\spam}[1]{\SSpan #1}

\newcommand{\Null}[1]{\NNull #1}

%

% shorter definitions for common usages

%

\newcommand{\ba}{\begin{array}}

\newcommand{\ea}{\end{array}}

\newcommand{\bc}{\begin{center}}

\newcommand{\ec}{\end{center}} \newcommand{\ds}{\displaystyle}

\newcommand{\arrayc}[1]{\ba{c} #1 \ea}

\newcommand{\be}{\begin{equation}}

\newcommand{\ee}{\end{equation}}

%

% problem definitions and mathematical constructions

%

\newcommand{\argmin}{\insmat{argmin}}

\DeclareOption{italian}

{

\newcommand{\subjectto}{\insmat{soggetto a}}

\newcommand{\maximize}{\insmat{max}}

\newcommand{\minimize}{\insmat{min}}

}

\DeclareOption{english}

{

\newcommand{\subjectto}{\insmat{subject to}}

\newcommand{\maximize} {\insmat{max}}

\newcommand{\minimize} {\insmat{min}}

}

\ProcessOptions

\newcommand{\eeqncond}[3]

{\begin{equation} \ba{rl} #1 & \mbox{ #2} \ea \label{#3}

\end{equation}}

\newcommand{\eqncond}[2]

{\[ \ba{rl} #1 & \mbox{ #2} \ea \] }

\newcommand{\simpleproblem}[3]

{\ba{lc} {\ds #3_{#2}} & {#1} \ea}

\newcommand{\epmin}[3]

{\begin{equation} \simpleproblem{#1}{#2}{\minimize} \label{#3}

\end{equation}}

\newcommand{\pmin}[2]

{\[ \simpleproblem{#1}{#2}{\minimize} \] }

\newcommand{\epmax}[3]

{\begin{equation} \simpleproblem{#1}{#2}{\maximize} \label{#3}

\end{equation}}

\newcommand{\pmax}[2]

{\[ \simpleproblem{#1}{#2}{\maximize} \] }

\newcommand{\problem}[4]

{\ba{lc} {\ds #4_{#1}} & {#2} \\*

{\subjectto} & {\ba[t]{c} #3 \ea}

\ea}

\newcommand{\eprobmin}[4]

{\begin{equation} \problem{#1}{#2}{#3}{\minimize} \label{#4}

\end{equation}}

\newcommand{\probmin}[3]

{\[ \problem{#1}{#2}{#3}{\minimize} \] }

\newcommand{\eprobmax}[4]

{\begin{equation} \problem{#1}{#2}{#3}{\maximize} \label{#4}

\end{equation}}

\newcommand{\probmax}[3]

{\[ \problem{#1}{#2}{#3}{\maximize} \] }

\newcommand{\compproblem}[2]

{ \ba{rcl} #2 \ge 0 \\* #1 \ge 0 \\* \ip{#1}{#2} = 0 \ea }

\newcommand{\compproblemb}[2]

{ \ba{rcl} #2 \ge 0 \\* #1 \ge 0 \\* \ip{#1}{(#2)} = 0 \ea }

\newcommand{\ecomp}[3]

{\begin{equation}

\compproblem{#1}{#2} \label{#3}

\end{equation}}

\newcommand{\ecompb}[3]

{\begin{equation}

\compproblemb{#1}{#2} \label{#3}

\end{equation}}

\newcommand{\comp}[2]

{\[ \compproblem{#1}{#2} \] }

\newcommand{\compb}[2]

{\[ \compproblemb{#1}{#2} \] }

%

% theorem and the like

%

\@ifundefined {flalign}

{

\def\emptybox

{

{\ \vbox{\hrule \hbox%

{%

\vrule height 1.3ex%

\hskip 0.8ex\vrule%

}\hrule%

}

}

}

\def\qed{\emptybox}

\def\endproof{\par \hfill \qed \par}

} { }

\DeclareOption{italian}

{

\newtheorem{thm}{Teorema}[section]

\newtheorem{cor}[thm]{Corollario}

\newtheorem{lem}[thm]{Lemma}

\newtheorem{prop}[thm]{Proposizione}

\newtheorem{fact}{Fatto}[section]

\@ifundefined {flalign} { }

{

\theoremstyle{definition}

}

\newtheorem{defn}{Definizione}[section]

\@ifundefined {flalign} { }

{

\theoremstyle{remark}

}

\newtheorem{remark}{Nota}[section]

\@ifundefined {flalign} { }

{

\theoremstyle{remark}

}

\newtheorem{Note}[remark]{Nota}

\newtheorem{conjecture}{Congettura}[section]

\newtheorem{exa}{Esempio}[section]

\@ifundefined {flalign}

{

\def\proof{\par\noindent{%

{\bf Dimostrazione.}%

\ignorespaces}}{ }

}

{

\renewcommand{\proofname}{Dimostrazione}

}

}

\DeclareOption{english}

{

\newtheorem{thm}{Theorem}[section]

\newtheorem{cor}[thm]{Corollary}

\newtheorem{lem}[thm]{Lemma}

\newtheorem{prop}[thm]{Proposition}

\newtheorem{fact}{Fact}[section]

\@ifundefined {flalign} { }

{

\theoremstyle{definition}

}

\newtheorem{defn}{Definition}[section]

\@ifundefined {flalign} { }

{

\theoremstyle{remark}

}

\newtheorem{remark}{Remark}[section]

\newtheorem{Note}[remark]{Remark}

\newtheorem{conjecture}{Conjecture}[section]

\newtheorem{exa}{Example}[section]

\@ifundefined {flalign}

{

\def\proof{\par\noindent{%

{\bf Proof.}%

\ignorespaces}}{ }

}{ }

}

\ProcessOptions

%\def\proof{\par\noindent{%

% \ifx\dateitalian\undefined%

% {\bf Proof}%

% \else%

% {\bf Dimostrazione}%

% . \ignorespaces}}

%\def\endproof {\par \hfill \emptybox \par}

%\def\blackbox{\vrule height 1.3ex width 0.8ex }

%\def\emptybox

%{

% {\ \vbox{\hrule \hbox%

% {%

% \vrule height 1.3ex%

% \hskip 0.8ex\vrule%

% }\hrule%

% }

% }

%}

%

% definition command

%

\makeatletter

\@ifundefined {flalign}

{

\newcommand\ifdefin[5]

{\[ #1 \define \left \{

\begin{array}{ll}

#2 & #3 \\ \\

#4 & #5

\end{array}

\right . \] }

}{ }

\makeatother

now can you tell me how can i introduce this function, so that jsMath can compile it like another mathematic command?

thank you Davide