# A report on Actor model theory

In theoretical computer science, Actor model theory concerns theoretical issues for the Actor model.

- Actor model theory3 related topics with Alpha

## Actor model

2 linksMathematical model of concurrent computation that treats actor as the universal primitive of concurrent computation.

Mathematical model of concurrent computation that treats actor as the universal primitive of concurrent computation.

It has been used both as a framework for a theoretical understanding of computation and as the theoretical basis for several practical implementations of concurrent systems.

## Denotational semantics of the Actor model

1 linksSubject of denotational domain theory for Actors.

Subject of denotational domain theory for Actors.

The augmented Actor event diagrams [see Actor model theory] form a partially ordered set < Diagrams, ≤ > from which to construct the power domain P[Diagrams] (see the section on Denotations below). The augmented diagrams are partial computation histories representing "snapshots" [relative to some frame of reference] of a computation on its way to being completed. For x,y∈Diagrams, x≤y means x is a stage the computation could go through on its way to y. The completed elements of Diagrams represent computations that have terminated and nonterminating computations that have become infinite. The completed elements may be characterized abstractly as the maximal elements of Diagrams [see William Wadge 1979]. Concretely, the completed elements are those having non pending events. Intuitively, Diagrams is not ω-complete because there exist increasing sequences of finite partial computations

## Indeterminacy in concurrent computation

1 linksConcerned with the effects of indeterminacy in concurrent computation.

Concerned with the effects of indeterminacy in concurrent computation.

Hewitt [1985] and Agha [1991], and other published work argued that mathematical models of concurrency did not determine particular concurrent computations as follows: The Actor model makes use of arbitration (often in the form of notional arbiters) for determining which message is next in the arrival ordering of an Actor that is sent multiple messages concurrently.