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This file is part of Logtalk https://logtalk.org/ SPDX-FileCopyrightText: 1998-2023 Paulo Moura <pmoura@logtalk.org> SPDX-License-Identifier: Apache-2.0

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

To load this example and for sample queries, please see the SCRIPT.txt file.

This folder contains Logtalk versions of two examples of network modeling for recognizing polyhedra represented as graphs as described in the following paper:

@inproceedings{Markov1989AFF,
        title={A Framework for Network Modeling in Prolog},
        author={Z. I. Markov},
        booktitle={IJCAI},
        year={1989}
}

A copy of the paper can be downloaded from:

https://www.ijcai.org/Proceedings/89-1/Papers/013.pdf

The Logtalk version uses parametric objects to represent the concept of "net-variables" described in the paper as "global logical variables" and the coroutining library to approximate the semantics of the original examples. The object parameter variables provide object "global logical variables". The implicit use of the dif/2 constraint is mentioned in the paper third page: "(The use of a special Prolog extension, ensuring all different variables to be bound to different objects, is essential in this example. Such an extension is also available in Prolog III.)".

Note that the use of the dif library limits the backend Prolog systems that can be used to run this example to B-Prolog, ECLiPSe, XVM, SICStus Prolog, SWI-Prolog, Trealla Prolog, XSB, and YAP.