Abstract
Call a subsetA of an ordered setP retractable tob ε P↠ iff the map that mapsA tob and leaves all other points fixed is a retraction. We prove fixed point theorems for sets that contain a retractable set and also use this tool to study the fixed point property for products. The results in this paper show that three classical approaches to the fixed point property: irreducible points, cutsets and lexicographic sums can be viewed as special cases of the situation described above.
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This research was funded in part by ONR grant nr. N00014-89-J-1824.
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Schröder, B.S.W. On retractable sets and the fixed point property. Algebra Universalis 33, 149–158 (1995). https://doi.org/10.1007/BF01190926
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DOI: https://doi.org/10.1007/BF01190926