(no subject)

David Feuer [email protected]
Mon, 10 Dec 2001 19:17:43 -0500

uma kompella wrote:
> hi
> i am new to haskell and am having a problem to write
> function which takes a boolean expression and returns
> a truthvalue stating whether or not it is a tautology.
> Can anyone please help me??
> Thanks a lot
> uma

I assume this is your homework.  It is better to say so explicitly.

Think about this:  what does it mean for an expression to be a
tautology?  Can you think of an a way to check this?  Once you've come
up with a way to check this, it should be quite easy to write it in
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