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Keywords:
complete lattice; closure operator; fixpoint; frame coproduct; compact frame
complete lattice; closure operator; fixpoint; frame coproduct; compact frame
Summary:
A constructively valid counterpart to Bourbaki's Fixpoint Lemma for chain-complete partially ordered sets is presented to obtain a condition for one closure system in a complete lattice $L$ to be stable under another closure operator of $L$. This is then used to deal with coproducts and other aspects of frames.
References:
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