Dear Gabin,
Your approach looks reasonable! Regarding the last term: try to write down each explicitly as a sum of products (regret when choosing arm times the probability of arm looking the best). Moreover, note that the latter probability can be upper bounded by the prob. that arm looks better than just the optimal arm (arm 1 by convention).
You might also want to take a look at my recent post in the discussion forum.
Best,
Thomas
Your approach looks reasonable! Regarding the last term: try to write down each explicitly as a sum of products (regret when choosing arm times the probability of arm looking the best). Moreover, note that the latter probability can be upper bounded by the prob. that arm looks better than just the optimal arm (arm 1 by convention).
You might also want to take a look at my recent post in the discussion forum.
Best,
Thomas