[Retros] DR vs forced ep: what rule predominates?

Rol, Guus G.A.Rol at umcutrecht.nl
Wed Aug 29 05:13:20 EDT 2007

In my opnion such a construct is not possible. The variation that contains "the AP-choice to be validated" plus "its validation moves" must have the potential of becoming a continuus reality. Since "deadness" is considered a game terminator here, it can never in reality be followed by validation moves. Or in formal terms: "no proof game can exist that contains a dead position followed by moves".

However, it is possible to include dead reckoning in an AP validation line, provided there is an appropriate interpretation of "nested legalities". This is a tricky subject, the same subject that started the discussion in this thread with e.p. and DR in the first place. In my view all play in virtual phases such as post-mate, post-stalemate, post-dead and AP-validation-evaluations must be considered in a different legality context than the legality on the (higher) level they are evaluating for. "Every move beyond stalemate is illegal but how can you decide on stalemate if you cannot attempt legal moves?". Andrew Buchanan has suggested the term "valid move" for this less restricted version of the "legal move". Without such a qualitative dinstiction, queries like this one are unapproachable.

Guus Rol.

-----Oorspronkelijk bericht-----
Van: retros-bounces at janko.at [mailto:retros-bounces at janko.at] Namens Otto Janko
Verzonden: dinsdag 28 augustus 2007 18:59
Aan: 'The Retrograde Analysis Mailing List'
Onderwerp: Re: [Retros] DR vs forced ep: what rule predominates?

What about an "a posteriori" validation of a dead position? E.g. a move validates that the position before this move was dead. Can anyone construct such a problem?


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