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  2. AC-3 algorithm - Wikipedia

    en.wikipedia.org/wiki/AC-3_algorithm

    Notice that the actual constraint graph representing this problem must contain two edges between X and Y since C2 is undirected but the graph representation being used by AC-3 is directed. AC-3 solves the problem by first removing the non-even values from of the domain of X as required by C1, leaving D(X) = { 0, 2, 4 }. It then examines the ...

  3. Hidden transformation - Wikipedia

    en.wikipedia.org/wiki/Hidden_transformation

    Constraints with one, two, or more variables are called unary, binary, or higher-order constraints. The number of variables in a constraint is called its arity. The hidden transformation replaces each constraint with a new, hidden variable. The hidden transformation converts an arbitrary constraint satisfaction problem into a binary one.

  4. List of PSPACE-complete problems - Wikipedia

    en.wikipedia.org/wiki/List_of_PSPACE-complete...

    Deterministic constraint logic (unbounded) [47] Dynamic graph reliability. [22] Graph coloring game [48] Node Kayles game and clique-forming game: [49] two players alternately select vertices and the induced subgraph must be an independent set (resp. clique). The last to play wins. Nondeterministic Constraint Logic (unbounded) [11]

  5. Local consistency - Wikipedia

    en.wikipedia.org/wiki/Local_consistency

    The AC-3 algorithm improves over this algorithm by ignoring constraints that have not been modified since they were last analyzed. In particular, it works on a set of constraints that initially contains all constraints; at each step, it takes a constraint and enforces arc consistency; if this operation may have produced a violation of arc ...

  6. Difference bound matrix - Wikipedia

    en.wikipedia.org/wiki/Difference_bound_matrix

    In model checking, a field of computer science, a difference bound matrix (DBM) is a data structure used to represent some convex polytopes called zones.This structure can be used to efficiently implement some geometrical operations over zones, such as testing emptyness, inclusion, equality, and computing the intersection and the sum of two zones.

  7. Domain-key normal form - Wikipedia

    en.wikipedia.org/wiki/Domain-key_normal_form

    Domain-key normal form (DK/NF or DKNF) is a normal form used in database normalization which requires that the database contains no constraints other than domain constraints and key constraints. A domain constraint specifies the permissible values for a given attribute, while a key constraint specifies the attributes that uniquely identify a ...

  8. Functional dependency - Wikipedia

    en.wikipedia.org/wiki/Functional_dependency

    In relational database theory, a functional dependency is the following constraint between two attribute sets in a relation: Given a relation R and attribute sets ,, X is said to functionally determine Y (written X → Y) if each X value is associated with precisely one Y value.

  9. Many-to-many (data model) - Wikipedia

    en.wikipedia.org/wiki/Many-to-many_(data_model)

    For example, think of A as Authors, and B as Books. An Author can write several Books, and a Book can be written by several Authors. In a relational database management system, such relationships are usually implemented by means of an associative table (also known as join table, junction table or cross-reference table), say, AB with two one-to-many relationships A → AB and B → AB.