7 IR models based on predicate logic
7 IR models based on predicate logic
7 IR models based on predicate logic
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<str<strong>on</strong>g>IR</str<strong>on</strong>g> <str<strong>on</strong>g>models</str<strong>on</strong>g> <str<strong>on</strong>g>based</str<strong>on</strong>g> <strong>on</strong> <strong>predicate</strong> <strong>logic</strong> 28<br />
computati<strong>on</strong> of probabilities for event expressi<strong>on</strong>s<br />
1. transformati<strong>on</strong> of expressi<strong>on</strong> into disjunctive normal<br />
form<br />
2. applicati<strong>on</strong> of sieve formula:<br />
c i – c<strong>on</strong>junct of event keys<br />
P (c 1 ∨ . . . ∨ c n ) =<br />
n∑<br />
(−1) i−1<br />
i=1<br />
∑<br />
1≤j 1
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