|concern = Per [[Wikipedia_talk:WikiProject_Mathematics#Subclass_reachability]], does not appear to be a notable concept. Redirecting to a parent topic would be UNDUE per that discussion.
|timestamp = 20211118225128
|nom = Premeditated Chaos
|help = off
}}
{{Multiple issues|
{{unreferenced|date=January 2009}}
{{orphan|date=November 2011}}
{{context|date=February 2011}}
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In [[computational learning theory]] in [[mathematics]], given a [[Concept class|class of concepts]] C, a subclass D is '''reachable''' if there exists a partial approximation S of some concept such that D contains exactly those concepts in C that are extensions to S (i.e., D=C|S).
