pescetom, on 2021-April-03, 09:29, said:
Nobody can disagree that there is UI (Law 16 says so clearly and Law 75A more cryptically) so is is no surprise that he too takes this for granted.
But he seems to think that the partnership agreement is AI even if East had forgotten it and was reminded by partner - which looking at 16A1d does not seem unreasonable (if you asked East between hands what the agreement about 1H 3N was, he would reply "splinter in the other major"). Unless some law (and presumably not 16 itself) precludes use of this information.
Thanks, I see what you mean now. This is interesting.
My initial thought was that given East thought 3N was natural, and 4N was a perfectly reasonable quantitative bid, it's not logical that they could suddenly have remembered 3NT actually wasn't natural. While that seems extremely unlikely, I guess it's possible.
In fact, 16B1(b) clearly states that logical alternatives are determined based on
using the methods of the partnership (even if you had temporarily forgotten what those methods are). Not based on what the player is likely to have thought those methods were at the time.
But if that's true, and you apply it to this situation, 5
♣ is a logical alternative if a significant proportion of players would answer yes to this question:
"You play 3NT as a splinter, but bid 3NT with your hand anyway. Do you now seriously consider 5
♣?"
Nobody would answer yes to that.
So going strictly by the laws, 5
♣ cannot be a LA.
On the other hand, if that's the correct interpretation, then that somewhat contradicts 75A, since forgetting your agreement and being reminded by partner would basically always turn out to be AI.
If being reminded is UI, then (even if the law isn't worded precisely), logical alternatives should be based on what you thought before receiving that UI. In which case, the poll would be that 4NT is natural, and nobody would bid 5
♣ over that.
In both cases, 5
♣ is not logical.
The director is in a sense arguing that the knowledge is both UI and AI at the same time, which really doesn't seem right. But even if it were, what polling question would result in 5
♣ being considered by most players?