ltms — a Python logic-based Truth Maintenance System and reasoning engine
Copyright (c) 2026 pisanuw. Licensed under the MIT License (see LICENSE).

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Attribution / provenance
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This project is an independent, clean-room Python reimplementation of the
algorithms and architecture described in:

    Kenneth D. Forbus and Johan de Kleer,
    "Building Problem Solvers", MIT Press, 1993.

The original reference implementation is in Common Lisp:

    Copyright (c) 1986-1993 Kenneth D. Forbus, Johan de Kleer and
    Xerox Corporation. All Rights Reserved.

The Building Problem Solvers reference code is distributed by the authors under
a permissive notice that allows use, reproduction, and the preparation of
derivative works provided the original copyright notice accompanies such works.
This Python project is an independent reimplementation informed by those
algorithms; it does not copy the original source code. The original code and the
book are available from the Northwestern Qualitative Reasoning Group:

    https://www.qrg.northwestern.edu/BPS/readme.html

The book's full text PDF is made available there for free download "thanks to
the gracious permission of MIT Press"; MIT Press retains the print rights. The
book text and PDF are NOT redistributed in this repository.
