The Language E

The Language E and the E-RES System

The Language E is a specialized, high-level logic for representing information about the occurrence and effects of actions and events. Its model-theoretic semantics defines what conclusions may be inferred from a given domain description written in E's vocabulary of simple propositional statements. The E-RES system, written in Prolog, automates the reasoning process implicit in E's semantics. The computation underlying E-RES is based on a translation of the Language E into an argumentation framework. Both the language and the system have been developed to provide a theoretical and computational framework for developing applications in artificial intelligence and computer science such as simulation, planning, fault diagnosis, temporal databases and cognitive robotics.

Click here for a list of associated papers.

The E-RES System

The distributed implementation of the E-RES System is based on the work of Antonis Kakas, Rob Miller and Francesca Toni and has been developed by Neophytos Demetriou, Antonis Kakas and Loizos Michael.

Click on the following links to download the latest version of the E-RES System and a variety of test domains. The E-RES System can be executed on any Windows 9x / Linux machine that runs ECLiPSe 5.0 and Tcl/Tk 8.3; later versions of Windows, ECLiPSe and Tcl/Tk are not expected to present any problems. To use the system, unzip the downloaded archive using WinZip (or any other appropriate program) and execute the appropriate file ("e-res.tcl" or "linux-eres").

eres-1.1 [ Unix | Windows ]: This file contains two variants of the E-RES System. One of the variants uses a Sat solver (*) to satisfy the ramifications of the domain. Make sure you read the README file first.

domains.zip: This file contains a variety of test domains, including those described in [6] above and some variations. These domains are also included in the "e-res.tar.gz" file above.

Language E Syntax

Each proposition should start on a new line, and span only one line. Each proposition should be of one of the forms in the table below, where:

"F" is a single word written with lower and upper case letters and digits naming a fluent constant,

"L", "L1", etc. represent fluent literals and are of the form "F" or "-F" where "F" is a fluent constant,

"A" is a single word written with lower and upper case letters and digits naming an action constant, and

"T" is a single whole number naming a time-point.

Proposition Type Allowed Form

t-proposition L holds-at T

h-proposition A happens-at T

c-proposition A initiates F
A initiates F when {L₁,...,L_n}
A terminates F
A terminates F when {L₁,...,L_n}

r-proposition L whenever {L₁,...,L_n}

const-fluent L is_constant

o-action A is_abducible

precondition A needs {L₁,...,L_n}

priority A₁ has_priority A₂ for {L₁,...,L_n}

Further Information

For further information please email Neophytos Demetriou (cs97dn1@ucy.ac.cy), Antonis Kakas (antonis@cs.ucy.ac.cy) or Loizos Michael (cs98ml1@ucy.ac.cy).

(*) The Sat solver currently used is a modified version of RelSat 2.00 by Roberto Bayardo.

Last updated: July 15, 2001.