"9" . _:vb7011260 . _:vb7011260 "(mathematics) Distinguished among entities of its kind, so that it can be picked out in a way that does not depend on any arbitrary choices."@en . _:vb7011261 "It turns out that ordered pairs can be defined in set theory, e.g. as \u00A0\u00A0\u00A0\u00A0\u00A0\u00A0\u00A0\u00A0(x, y) :=\\{\\{x, y\\}, y\\}. Note that in no sense is such a definition canonical."@en . _:vb7011261 "2011 July 2, Samson Abramsky with Nikos Tzevelekos, \u201CIntroduction to Categories and Categorical Logic\u201D, in (Please provide the book title or journal name)\u200E[1], page 19:"@en . . _:vb7011261 .