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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> 33<br />

Probabilistic rules<br />

rules for deterministic facts:<br />

0.7 likes-sports(X) :- man(X).<br />

0.4 likes-sports(X) :- woman(X).<br />

man(peter).<br />

interpretati<strong>on</strong>:<br />

P (W 1 ) = 0.7: {man(peter),<br />

likes-sports(peter)}<br />

P (W 2 ) = 0.3: {man(peter)}<br />

rules for uncertain facts:<br />

# sex(dk,av).<br />

0.7 l-s(X) :- sex(X,male).<br />

0.4 l-s(X) :- sex(X,female).<br />

0.5 sex(X,male) :- human(X).<br />

0.5 sex(X,female) :- human(X).<br />

human(peter).<br />

interpretati<strong>on</strong>:<br />

P (W 1 ) = 0.35: {sex(peter,male), l-s(peter)}<br />

P (W 2 ) = 0.15: {sex(peter,male)}<br />

P (W 3 ) = 0.20: {sex(peter,female), l-s(peter)}<br />

P (W 4 ) = 0.30: {sex(peter,female)}<br />

Norbert Fuhr

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