MIT
17
Analysis I
l
Min-cut is small---few edges
»
Suppose graph has min-cut
c
»
Then minimum degree at least
c
»
Thus at least
nc
/
2
edges
l
Random
edge is probably safe
l
Pr[min-cut edge]
£
c
/
(
nc
/
2)
l
=
2
/
n
l
(easy generalization to capacitated case)