Source : Free On-Line Dictionary of Computing

linear function
     
        A {recursive} function is linear if it is of the form
     
        	f x = if p x then q x else h f x
     
        where h is a "linear functional" which means that
     
        (1) for all functions, a, b c and some function ht
     
        	h (if a then b else c) = if ht a then h b else h c
     
        Function ht is known as the "predicate transformer" of h.
     
        (2) If for some x,
     
        	h (\ y . bottom) x  /=  bottom
     
        then
     
        	for all g,  ht g x  =  True.
     
        I.e. if h g x terminates despite g x not terminating then ht g
        x doesn't depend on g.
     
        See also {linear argument}.
     
        (1995-02-15)