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        <article-title>Logic Programming and Non-monotonic Reasoning from 1991 to 2019: a Personal Perspective</article-title>
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      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Michael Gelfond</string-name>
          <email>michael.gelfond@ttu.edu</email>
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          <label>0</label>
          <institution>Texas Tech University</institution>
          ,
          <country country="US">USA</country>
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      <p>The eld of logic programming and nonmonotic reasoning was born in 1991,
when a number of researchers working in \the theoretical ends" of logic
programming and arti cial intelligence gathered in Washington D.C. for the rst
LPNMR workshop, which was organized by Anil Nerode, Wiktor Marek, and
V.S. Subrahmanian. I was privileged to attend this meeting; to closely observe
the development of the eld over the past 28 years; and to witness many
remarkable achievements, which in 1991 I would not have believed to be possible. In this
talk I plan to discuss some of these achievements and share a number of personal
observations on the eld's history, current state, and possible future directions.
Among other things, I will comment on the development of powerful knowledge
representation languages, the design and implementation of non-monotonic
reasoning systems, and use of these languages and systems in formalizing various
types of knowledge and reasoning tasks. The talk is not meant to be a survey of
the eld, rather it is my personal perspective limited to a small, but important,
collection of topics I am most familiar with.</p>
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