Your proof is sound, but form an aesthetic viewpoint, I've never really liked proofs by induction. There's just something too brutishforce about them for my taste. But ... we all have our quirks.
Also, even glossing over the ambiguous nature of proofbyobviousness and assuming what you say is true, your lemma only shows that the probability is the *same*, not what the probability *is*. Perhaps a corollary or a separate claim/lemma/theorem is in order.
Last fiddled with by ewmayer on 20070801 at 18:30
