FO(.): Difference between revisions
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Revision as of 09:23, 1 February 2022
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In computer science, FO(.) (a.k.a. FO-dot) is a knowledge representation language based on first-order logic.[1]
It has 4 types of statements:
- Function and predicate declarations,
- Axioms, i.e., logic sentences about possible worlds,
- Definitions that specify a unique interpretation of a defined symbol, given the interpretation of its parameters. Definitions can be inductive.
- Enumerations, i.e., definitions of symbols by enumeration.
An FO-dot knowledge base cannot be run. It is a "bag of information", to be used as input to various generic reasoning algorithms: e.g., to determine relevant questions, to compute consequences of new facts, and to explain them.
FO(.) extends first-Order logic with: types, aggregates, arithmetic, (inductive) definitions, partial functions, and intensional objects.
FO-dot is used by these reasoning engines:
- IDP-Z3[2]
- FOLASP[5]
Example
The following voting laws
- you must be at least 18 years old to vote;
- if the law is prescriptive, voting is mandatory.
can represented in FO(.) as follows:
vocabulary V{
age: () → ℤ // function declaration
prescriptive, vote: () → 𝔹 // predicate declarations
}
theory T:V {
age()< 18 ⇒ ¬vote(). // axiom: if you are less than 18, you may not vote.
prescriptive() ⇒ (age()≥ 18 ⇒ vote()). // axiom: if prescriptive: if you are at least 18, you must vote
}
In this code, A→
B indicates a function from A to B; 𝔹 denotes the booleans, ¬
denotes negation, and ⇒
denotes material conditional. Predicates < and ≥ are built-in and have their usual meaning.
Such knowledge base can be turned automatically into an Interactive Lawyer[6] (see here[7])
References
- ^ Denecker, Marc (2000). "Extending classical logic with inductive definitions". International Conference on Computational Logic: 703–717.
- ^ "IDP-Z3". Retrieved 2022-02-01.
- ^ De Cat, Broes; Bogaerts, Bart; Bruynooghe, Maurice; Janssens, Gerda; Denecker, Marc (2018). "Predicate logic as a modeling language: the IDP system". Declarative Logic Programming: Theory, Systems, and Applications: 279–323. doi:10.1145/3191315.3191321.
- ^ "IDP". Retrieved 2022-02-01.
- ^ "FOLASP". Retrieved 2022-02-01.
- ^ "Interactive Consultant". Retrieved 2022-02-01.
- ^ "Interactive Consultant". Retrieved 2022-02-01.