Transaction logic

Transaction Logic is an extension of predicate logic that accounts in a clean and declarative way for the phenomenon of state changes in logic programs and databases. This extension adds connectives specifically designed for combining simple actions into complex transactions and for providing control over their execution. The logic has a natural model theory and a sound and complete proof theory. Transaction Logic has a Horn clause subset, which has a procedural as well as a declarative semantics. The important features of the logic include hypothetical and committed updates, dynamic constraints on transaction execution, non-determinism, and bulk updates. In this way, Transaction Logic is able to declaratively capture a number of non-logical phenomena, including procedural knowledge in artificial intelligence, active databases, and methods with side effects in object databases.

Examples

Graph coloring Here denotes the elementary update operation of transactional insert. The connective is called serial conjunction. colorNode Pyramid stacking The elementary update represents the transactional delete operation. stack(N,X) 0 ⊗ move(Y,X) ⊗ stack(N-1,Y). stack(0,X). move(X,Y) Hypothetical execution Here is the modal operator of possibility: If both and are possible, execute . Otherwise, if only is possible, then execute it. execute action1 ⊗ <>action2 ⊗ action1. execute action1 ⊗ <>action2 ⊗ action2. Dining philosophers Here is the logical connective of parallel conjunction of Concurrent Transaction Logic. diningPhilosophers == Implementations ==

Implementations

A number of implementations of Transaction Logic exist: • The original implementation. • An implementation of Concurrent Transaction Logic. • Transaction Logic enhanced with tabling. An implementation of Transaction Logic has also been incorporated as part of the Flora-2 knowledge representation and reasoning system. All these implementations are open source. == References ==

Source: Wikipedia ↗

tickerdossier.com tickerdossier.substack.com