**What is the latest?**- The current version of QEPCADB is Version B 1.71, 30 January 2018. See LOG of recent important changes.
**What is QEPCAD?**- QEPCAD is an implementation of quantifier elimination by
partial cylindrical algebraic decomposition due orginally to
Hoon Hong, and subsequently added on to by many others. It is
an interactive command-line program written in C, and based on
the SACLIB library of computer algebra functions. Presented here is
QEPCAD B version 1,
the "B"
designating a substantial departure from the original QEPCAD
and distinguishing it from any development of the original
that may proceed in a different direction.
**More Information ...** **What is Quantifier Elimination?**- Quantifier elimination algorithms allow us to answer
questions about
*semi-algebraic sets*, which are subsets of real*n*-dimensional space whose boundaries are defined by polynomial equations.**More Information ...** **How do I use QEPCAD?**- QEPCAD is an interactive command-line driven program. At
its simplest you enter a formula like "there exists an
`x`

such that`[ x^2 + b x + c = 0 ]`

" and QEPCAD returns a formula like "`[ b^2 - 4 c >= 0]`

", which is equivalent to the input when`x`

,`b`

and`c`

are assumed to range over the real numbers. However, QEPCAD's interactive interface allows the user control of how problems are solved and what kinds of answers are given, and making good use of this interface can drastically reduce the time and space required to solve problems and improve the quality of QEPCAD's results.**More Information ...** **How do I get/install QEPCAD?**-
We have QEPCAD available for Sun Solaris and Linux. What we
provide is the source code for the SACLIB library and QEPCAD.
If you have the gcc compiler and a few other standard tools
available, you should be able to compile and run QEPCAD
without too much trouble ... I hope!
**More Information ...**

Christopher W Brown Last modified: Thu Apr 15 14:02:46 EDT 2010