Editing Exponential hierarchy (section)

In [[computational complexity theory]], the '''exponential hierarchy''' is a hierarchy of [[complexity class]]es that is an [[EXPTIME|exponential time]] analogue of the [[polynomial hierarchy]]. As elsewhere in complexity theory, “exponential” is used in two different meanings (linear exponential bounds <math>2^{cn}</math> for a constant ''c'', and full exponential bounds <math>2^{n^c}</math>), leading to two versions of the exponential hierarchy.<ref>Sarah Mocas, Separating classes in the exponential-time hierarchy from classes in ''PH'', [[Theoretical Computer Science (journal)|Theoretical Computer Science]] 158 (1996), no.&nbsp;1–2, pp.&nbsp;221–231.</ref><ref name=":0">Anuj Dawar, Georg Gottlob, Lauri Hella, Capturing relativized complexity classes without order, Mathematical Logic Quarterly 44 (1998), no.&nbsp;1, pp.&nbsp;109–122.</ref> This hierarchy is sometimes also referred to as the ''weak'' exponential hierarchy, to differentiate it from the ''strong'' exponential hierarchy.<ref name=":0" /><ref>{{Cite journal|last=Hemachandra|first=Lane A.|date=1989|title=The strong exponential hierarchy collapses|url=|journal=[[Journal of Computer and System Sciences]]|language=en|volume=39|issue=3|pages=299–322|doi=10.1016/0022-0000(89)90025-1}}</ref>