= Andrés Caicedo
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<Andrés Caicedo> is the <mathematician> specializing in <set theory> identified as Andrés Eduardo Caicedo on his author homepage.https://websites.umich.edu/~caicedo/[Author homepage, mathematical identity]{ref} His published teaching notes develop infinite <partition relations>, including <omega-Jónsson functions> and their relationship to colourings of countably infinite <subsets>.<Partition calculus (3) by Andrés Caicedo>[Definition 1 and Theorem 2]{ref}
For an infinite <set> $X$, an <omega-Jónsson function> has the form $f:[X]^{\aleph_0}\to X$, and every $Y\subseteq X$ with $|Y|=|X|$ satisfies $f([Y]^{\aleph_0})=X$. Thus a large restriction still produces every colour. His notes present a proof of existence assuming the <axiom of choice>, explicitly attributing the theorem and the simplified proof to their discoverers. This is a concrete example of the interaction between <cardinal arithmetic> and infinite <combinatorics>.
\Image[https://websites.umich.edu/~caicedo/andres_2015.jpg]
{title=Andrés Eduardo Caicedo, Ann Arbor, June 2015; photograph by Juli Pinsak}
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