If we detect clone overlaps by comparing their restriction
fingerprints, an overlap is claimed only when the two clones share a
certain amount of fragments. In other words, small overlaps would not
be detected. If we have the minimal amount of overlaps to be detected,
the above analysis goes through with a little correction:
Ex 3. Suppose we only detect overlap if two clones overlap by more
than a fraction 
of their length (
). Show that
the preceding formula/arguments in the constant clone length case
apply with the length L replaced by the effective clone length 
.