Folks -- one of my students asked if it is possible to directly associate a mathematical property with a variable for use in derivations involving that variable. For example, can one associate the property that a variable a is a real number that is greater than zero when performing integrals and the like? I know that one can make this assumption in the Integrate command and in other commands via the option Assumptions -> a>0 , but it would be useful to be able to do this at the beginning of a series of derivations that involve the variable, without constantly having to repeat the Assumption at every step.
Thanks -- Dan Dubin, UCSD
Have you tried setting the global \$Assumptions?
Thanks, that's what I needed.