normal form
21Third normal form — The third normal form (3NF) is a normal form used in database normalization. 3NF was originally defined by E.F. CoddCodd, E.F. Further Normalization of the Data Base Relational Model. (Presented at Courant Computer Science Symposia Series 6, Data …
22Fourth normal form — (4NF) is a normal form used in database normalization. Introduced by Ronald Fagin in 1977, 4NF is the next level of normalization after Boyce Codd normal form (BCNF). Whereas the second, third, and Boyce Codd normal forms are concerned with… …
23Disjunctive normal form — In boolean logic, a disjunctive normal form (DNF) is a standardization (or normalization) of a logical formula which is a disjunction of conjunctive clauses. As a normal form, it is useful in automated theorem proving. A logical formula is… …
24Clausal normal form — The clausal normal form (or clause normal form, conjunctive normal form, CNF) of a logical formula is used in logic programming and many theorem proving systems. A formula in clause normal form is a set of clauses, interpreted as a conjunction. A …
25Second normal form — (2NF) is a normal form used in database normalization. 2NF was originally defined by E.F. CoddCodd, E.F. Further Normalization of the Data Base Relational Model. (Presented at Courant Computer Science Symposia Series 6, Data Base Systems, New… …
26Boyce-Codd normal form — (or BCNF) is a normal form used in database normalization. It is a slightly stronger version of the third normal form (3NF). A table is in Boyce Codd normal form if and only if, for every one of its non trivial functional dependencies X → Y , X… …
27Skolem normal form — A formula of first order logic is in Skolem normal form (named after Thoralf Skolem) if it is in conjunctive prenex normal form with only universal first order quantifiers. Every first order formula can be converted into Skolem normal form while… …
28Greibach normal form — In computer science, to say that a context free grammar is in Greibach normal form (GNF) means that all production rules are of the form::A o alpha X or:S o lambdawhere A is a nonterminal symbol, α is a terminal symbol, X is a (possibly empty)… …
29Negation normal form — A logical formula is in negation normal form if negation occurs only immediately above elementary propositions, and { } are the only allowed Boolean connectives. In classical logic each formula can be brought into this form by replacing… …
30Kuroda normal form — In formal language theory, a grammar is in Kuroda normal form iff all production rules are of the form:: AB rarr; CD or: A rarr; BC or: A rarr; B or: A rarr; α where A, B, C and D are nonterminal symbols and α is a terminal symbol.Every grammar… …
