Second-order cone programming: Difference between revisions

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Relation with other optimization problems: Rewrite part about convex semialgebraic sets to make the relation to SOCPs clearer
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When <math>A_i = 0</math> for <math>i = 1,\dots,m</math>, the SOCP reduces to a [[linear program]]. When <math>c_i = 0 </math> for <math>i = 1,\dots,m</math>, the SOCP is equivalent to a convex quadratically constrained linear program.
 
Convex [[quadratically constrained quadratic program]]s can also be formulated as SOCPs by reformulating the objective function as a constraint.<ref name=":0" /> [[Semidefinite programming]] subsumes SOCPs as the SOCP constraints can be written as [[linear matrix inequality|linear matrix inequalities]] (LMI) and can be reformulated as an instance of semidefinite program.<ref name=":0" /> The converse, however, is not valid: there are positive semidefinite cones that do not admit any second-order cone representation.<ref name="Fawzi">{{Cite journal|last=Fawzi|first=Hamza|date=2019|title=On representing the positive semidefinite cone using the second-order cone|journal=Mathematical Programming|language=en|volume=175|issue=1–2|pages=109–118|doi=10.1007/s10107-018-1233-0|issn=0025-5610|arxiv=1610.04901|s2cid=119324071}}</ref> In fact, while any

Any closed convex [[semialgebraic set]] in the plane can be written as a feasible region of a SOCP,<ref>{{cite arXiv|last=Scheiderer|first=Claus|date=2020-04-08|title=Second-order cone representation for convex subsets of the plane|class=math.OC|eprint=2004.04196}}</ref>. However, it is known that there exist convex semialgebraic sets of higher dimension that are not representable by SDPs, that is, there exist convex semialgebraic sets that can not be written as athe feasible region of a SDP (and, <em>a fortiori</em>, as the feasible region of a SOCP).<ref>{{Cite journal|last=Scheiderer|first=Claus|date=2018|title=Spectrahedral Shadows|journal=SIAM Journal on Applied Algebra and Geometry|language=en|volume=2|issue=1|pages=26–44|doi=10.1137/17M1118981|issn=2470-6566|doi-access=free}}</ref>
 
== Examples ==