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)
