Query Q

If we want to know whether K => Q

i.e. not K or Q is True i.e. K and not Q is False

In other words K augmented with not Q entails falsehood, for sure.

Resolution procidor may bot actual finish.

Resolution may never end; never (whatever algorithm): undecidability

Other resolution may take an huge time to be solved: intractability.

Propositional logic is decidbale, but intractable (SAT, NP ..).

Automates reasoning, semantic-web.

OWL-DL, OWL-lite (description logic: leader sets person ...) deci Statements about the structure of the world are not undecibebality but may intractability,

Horn logic is essential rules, like a person if there is only one conclusions on the right statement. Such statements are undecidable (except with caveats); but always tractable.

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