Off[General::spell]
Off[General::spell1]

$OperatingSystem

$HomeDirectory

\(\(If[$OperatingSystem\  == "Windows", $AbstractAlgebraPath = $TopDirectory <> "/AddOns/Applications/AbstractAlgebra/"; 
        AppendTo[$Path, $AbstractAlgebraPath], $AbstractAlgebraPath = 
          StringJoin[$HomeDirectory, "/.Mathematica/5.1/AddOns/Applications/AbstractAlgebra", "/"]];\)\)

$Path

Needs["AbstractAlgebra`Master`"]