Clarification, please, on monotonicity

All -

We have had several discussions of monotonic and non-monotonic behaviour of
drivers, but there is a point which remains ambiguous in my mind. When we
speak of monotonicity, do we mean strictly rising ( or falling ) waveforms,
or do we accept non-decreasing ( non-increasing ) waveforms as monotonic?
That is would a waveform be considered monotonic if it rose for a while,
flattened out to a number of equal values and then rose again? The question really is
does the derivative have to be always of the same sign, or is a derivative that
has a zero region acceptable as a definition of monotonic? According to the
strict mathematical definition, the derivative must be of the same sign and non-
zero over the interval of interest. But it seems to me that we are more
interested here in allowing the zero region of the derivative and so talking
about non_decreassing ( or non-increasing ). Either can make a valid working
definition, but it makes a difference as I code a test for the condition as to
which we mean.

Clarification? Comments?

Thanks,

 Bob bward@dadhb1.ti.com or bward@neosoft.com
Received on Tue Apr 26 06:31:34 1994