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Subject: Alpha-Beta explanation on Heinz's book?

Author: Severi Salminen

Date: 08:48:46 10/05/00


I ordered a copy of Heinz's book in the library of my home town. A few  question
about his AB explanation:

1.He says: "While fail-highs with result>=beta place lower bounds on the real
scores of failed searches, fail-lows with result<=alpha place upper bounds on

So, what bound is he meaning (maybe my english is not so good): real scores of
failed searches? I thought that Alpha and Beta are the only bounds involved -
they are the lower and upper bounds of real score, aren't they. Does this imply
in negamax implementation? I know basically what fail-high (and fail-low) means,
but didn't understand this statement.

2. I didn't understand the fail-hard concept? How would a fail-hard
implementation of AB work compared to fail-soft?


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