@@ -1,83 +1,83 @@ -\documentstyle[11pt,reduce]{article} -\title{A REDUCE Limits Package} -\date{} -\author{Stanley L. Kameny \\ Email: stan\%valley.uucp@rand.org} -\begin{document} -\maketitle - -\index{LIMITS package} -LIMITS is a fast limit package for REDUCE for functions which are -continuous except for computable poles and singularities, based on some -earlier work by Ian Cohen and John P. Fitch. The Truncated Power Series -package is used for non-critical points, at which the value of the -function is the constant term in the expansion around that point. -\index{l'H\^opital's rule} -l'H\^opital's rule is used in critical cases, with preprocessing of -$\infty - \infty$ forms and reformatting of product forms in order -to apply l'H\^opital's rule. A limited amount of bounded arithmetic -is also employed where applicable. - -\section{Normal entry points} -\ttindex{LIMIT} -\vspace{.1in} -\noindent {\tt LIMIT}(EXPRN:{\em algebraic}, VAR:{\em kernel}, -LIMPOINT:{\em algebraic}):{\em algebraic} -\vspace{.1in} - -This is the standard way of calling limit, applying all of the methods. The -result is the limit of EXPRN as VAR approaches LIMPOINT. - - -\section{Direction-dependent limits} - -\ttindex{LIMIT+} \ttindex{LIMIT-} -\vspace{.1in} -\noindent {\tt LIMIT!+}(EXPRN:{\em algebraic}, VAR:{\em kernel}, -LIMPOINT:{\em algebraic}):{\em algebraic} \\ -\noindent {\tt LIMIT!-}(EXPRN:{\em algebraic}, VAR:{\em kernel}, -LIMPOINT:{\em algebraic}):{\em algebraic} -\vspace{.1in} - -If the limit depends upon the direction of approach to the {\tt LIMPOINT}, -the functions {\tt LIMIT!+} and {\tt LIMIT!-} may be used. They are -defined by: - -\vspace{.1in} -\noindent{\tt LIMIT!+ (LIMIT!-)} (EXP,VAR,LIMPOINT) $\rightarrow$ \\ -\hspace*{2em}{\tt LIMIT}(EXP*,$\epsilon$,0) -EXP*=sub(VAR=VAR+(-)$\epsilon^2$,EXP) - -\section{Diagnostic Functions} - -\ttindex{LIMIT0} -\vspace{.1in} -\noindent {\tt LIMIT0}(EXPRN:{\em algebraic}, VAR:{\em kernel}, -LIMPOINT:{\em algebraic}):{\em algebraic} -\vspace{.1in} - -This function will use all parts of the limits package, but it does not -combine log terms before taking limits, so it may fail if there is a sum -of log terms which have a removable singularity in some of the terms. - -\ttindex{LIMIT1} -\vspace{.1in} -\noindent {\tt LIMIT1}(EXPRN:{\em algebraic}, VAR:{\em kernel}, -LIMPOINT:{\em algebraic}):{\em algebraic} -\vspace{.1in} - -\index{TPS package} -This function uses the TPS branch only, and will fail if the limit point is -singular. - -\ttindex{LIMIT2} -\vspace{.1in} -\begin{tabbing} -{\tt LIMIT2}(\=TOP:{\em algebraic}, \\ -\>BOT:{\em algebraic}, \\ -\>VAR:{\em kernel}, \\ -\>LIMPOINT:{\em algebraic}):{\em algebraic} -\end{tabbing} -\vspace{.1in} - -This function applies l'H\^opital's rule to the quotient (TOP/BOT). -\end{document} +\documentstyle[11pt,reduce]{article} +\title{A REDUCE Limits Package} +\date{} +\author{Stanley L. Kameny \\ Email: stan\%valley.uucp@rand.org} +\begin{document} +\maketitle + +\index{LIMITS package} +LIMITS is a fast limit package for REDUCE for functions which are +continuous except for computable poles and singularities, based on some +earlier work by Ian Cohen and John P. Fitch. The Truncated Power Series +package is used for non-critical points, at which the value of the +function is the constant term in the expansion around that point. +\index{l'H\^opital's rule} +l'H\^opital's rule is used in critical cases, with preprocessing of +$\infty - \infty$ forms and reformatting of product forms in order +to apply l'H\^opital's rule. A limited amount of bounded arithmetic +is also employed where applicable. + +\section{Normal entry points} +\ttindex{LIMIT} +\vspace{.1in} +\noindent {\tt LIMIT}(EXPRN:{\em algebraic}, VAR:{\em kernel}, +LIMPOINT:{\em algebraic}):{\em algebraic} +\vspace{.1in} + +This is the standard way of calling limit, applying all of the methods. The +result is the limit of EXPRN as VAR approaches LIMPOINT. + + +\section{Direction-dependent limits} + +\ttindex{LIMIT+} \ttindex{LIMIT-} +\vspace{.1in} +\noindent {\tt LIMIT!+}(EXPRN:{\em algebraic}, VAR:{\em kernel}, +LIMPOINT:{\em algebraic}):{\em algebraic} \\ +\noindent {\tt LIMIT!-}(EXPRN:{\em algebraic}, VAR:{\em kernel}, +LIMPOINT:{\em algebraic}):{\em algebraic} +\vspace{.1in} + +If the limit depends upon the direction of approach to the {\tt LIMPOINT}, +the functions {\tt LIMIT!+} and {\tt LIMIT!-} may be used. They are +defined by: + +\vspace{.1in} +\noindent{\tt LIMIT!+ (LIMIT!-)} (EXP,VAR,LIMPOINT) $\rightarrow$ \\ +\hspace*{2em}{\tt LIMIT}(EXP*,$\epsilon$,0) +EXP*=sub(VAR=VAR+(-)$\epsilon^2$,EXP) + +\section{Diagnostic Functions} + +\ttindex{LIMIT0} +\vspace{.1in} +\noindent {\tt LIMIT0}(EXPRN:{\em algebraic}, VAR:{\em kernel}, +LIMPOINT:{\em algebraic}):{\em algebraic} +\vspace{.1in} + +This function will use all parts of the limits package, but it does not +combine log terms before taking limits, so it may fail if there is a sum +of log terms which have a removable singularity in some of the terms. + +\ttindex{LIMIT1} +\vspace{.1in} +\noindent {\tt LIMIT1}(EXPRN:{\em algebraic}, VAR:{\em kernel}, +LIMPOINT:{\em algebraic}):{\em algebraic} +\vspace{.1in} + +\index{TPS package} +This function uses the TPS branch only, and will fail if the limit point is +singular. + +\ttindex{LIMIT2} +\vspace{.1in} +\begin{tabbing} +{\tt LIMIT2}(\=TOP:{\em algebraic}, \\ +\>BOT:{\em algebraic}, \\ +\>VAR:{\em kernel}, \\ +\>LIMPOINT:{\em algebraic}):{\em algebraic} +\end{tabbing} +\vspace{.1in} + +This function applies l'H\^opital's rule to the quotient (TOP/BOT). +\end{document}