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### 4.5 D-WFS and D-STABLE

Before we can state the definition of D-WFS we have to extend our principles to disjunctive programs with default-negation.

4.21. Definition

Disjunctive Logic Program

A disjunctive logic program consists of a finite number of rules of the form

${A}_{1}\vee \dots \vee {A}_{k}←{B}_{1},\dots ,{B}_{m},not{C}_{1},\dots ,not{C}_{n}$

where A 1 ,…,Ak, B 1 ,…,Bm,C 1 ,…,Cn are positive atoms (containing possibly free variables). We call A 1…Ak the head of the rule, B 1,,Bm its positive body and C1,,Cn its negative body. The comma represents conjunction ∧.

We abbreviate these rules by

$\mathcal{A}←{ℬ}^{+},not{ℬ}^{}$

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