function represents the expression to be simplified
Description:
The command simplify simplifies the expression given in argument
representing the function function. The command simplify does not
endanger the safety of computations even in Sollya's floating-point
environment: the function returned is mathematically equal to the
function function.
Remark that the simplification provided by simplify is not perfect:
they may exist simpler equivalent expressions for expressions returned
by simplify.