The Sharpest CutPub Date : 1900-01-01DOI: 10.1137/1.9780898718805.ch16
M. Laurent
{"title":"Semidefinite Relaxations for Max-Cut","authors":"M. Laurent","doi":"10.1137/1.9780898718805.ch16","DOIUrl":"https://doi.org/10.1137/1.9780898718805.ch16","url":null,"abstract":"We compare several semideenite relaxations for the cut polytope obtained by applying the lift and project methods of Lovv asz and Schrijver and of Lasserre. We show that the tightest relaxation is obtained when aplying the Lasserre construction to the node formulation of the max-cut problem. This relaxation Q t (G) can be deened as the projection on the edge subspace of the set F t (n), which consists of the matrices indexed by all subsets of 1; n] of cardinality t + 1 with the same parity as t + 1 and having the property that their (I; J)-th entry depends only on the symmetric diierence of the sets I and J. The set F 0 (n) is the basic semideenite relaxation of max-cut consisting of the semideenite matrices of order n with an all ones diagonal, while F n?2 (n) is the 2 n?1-dimensional simplex with the cut matrices as vertices. We show the following geometric properties: If Y 2 F t (n) has rank t + 1, then Y can be written as a convex combination of at most 2 t cut matrices, extending a result of Anjos and Wolkowicz for the case t = 1; any 2 t+1 cut matrices form a face of F t (n) for t = 0; 1; n ? 2. The class L t of the graphs G for which Q t (G) is the cut polytope of G is shown to be closed under taking minors. The graph K 7 is a forbidden minor for membership in L 2 , while K 3 and K 5 are the only minimal forbidden minors for the classes L 0 and L 1 , respectively.","PeriodicalId":416196,"journal":{"name":"The Sharpest Cut","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124064375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Sharpest CutPub Date : 1900-01-01DOI: 10.1137/1.9780898718805.ch10
D. Naddef
{"title":"The Domino Inequalities for the Symmetric Traveling Salesman Problem","authors":"D. Naddef","doi":"10.1137/1.9780898718805.ch10","DOIUrl":"https://doi.org/10.1137/1.9780898718805.ch10","url":null,"abstract":"An optical viewing device having a stabilized mirror in the objective lens system, the arrangement being such that the conditions for stabilization of the image against vibration about an axis perpendicular to the line of sight of the device is 2 2s 1 1 - + = r fr m WHERE R IS A COUPLING RATIO; S IS THE DISTANCE ALONG THE OPTICAL AXIS BETWEEN THE MIRROR AND A PART OF THE OBJECTIVE LENS SYSTEM THAT LIES IN FRONT OF THE REFLECTING SURFACE; F IS THE FOCAL LENGTH OF THAT PART OF THE OBJECTIVE LENS SYSTEM THAT LIES IN FRONT OF THE REPLECTING SURFACE; AND M IS THE OVERALL MAGNIFICATION OF THE COMPLETE OPTICAL SYSTEM OF THE DEVICE.","PeriodicalId":416196,"journal":{"name":"The Sharpest Cut","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122073395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Sharpest CutPub Date : 1900-01-01DOI: 10.1137/1.9780898718805.ch2
L. Wolsey
{"title":"Time for Old and New Faces","authors":"L. Wolsey","doi":"10.1137/1.9780898718805.ch2","DOIUrl":"https://doi.org/10.1137/1.9780898718805.ch2","url":null,"abstract":"","PeriodicalId":416196,"journal":{"name":"The Sharpest Cut","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131171925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Sharpest CutPub Date : 1900-01-01DOI: 10.1137/1.9780898718805.ch18
R. Bixby, M. Fenelon, Zonghao Gu, E. Rothberg, Roland Wunderling
{"title":"Mixed-Integer Programming: A Progress Report","authors":"R. Bixby, M. Fenelon, Zonghao Gu, E. Rothberg, Roland Wunderling","doi":"10.1137/1.9780898718805.ch18","DOIUrl":"https://doi.org/10.1137/1.9780898718805.ch18","url":null,"abstract":"","PeriodicalId":416196,"journal":{"name":"The Sharpest Cut","volume":"250 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131947999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Sharpest CutPub Date : 1900-01-01DOI: 10.1137/1.9780898718805.ch6
C. Gentile, U. Haus, M. Köppe, G. Rinaldi, R. Weismantel
{"title":"On the Way to Perfection: Primal Operations for Stable Sets in Graphs","authors":"C. Gentile, U. Haus, M. Köppe, G. Rinaldi, R. Weismantel","doi":"10.1137/1.9780898718805.ch6","DOIUrl":"https://doi.org/10.1137/1.9780898718805.ch6","url":null,"abstract":"In this paper some operations are described that transform every graph into a perfect graph by replacing nodes with sets of new nodes. The transformation is done in such a way that every stable set in the perfect graph corresponds to a stable set in the original graph. These operations yield a purely combinatorial augmentation procedure for finding a maximum weighted stable set in a graph. Starting with a stable set in a given graph one defines a simplex type tableau whose associated basic feasible solution is the incidence vector of the stable set. In an iterative fashion, non-basic columns that would lead to pivoting into non-integral basic feasible solutions, are replaced by new columns that one can read off from special graph structures such as odd holes, odd antiholes, and various generalizations. Eventually, either a pivot leading to an integral basic feasible solution is performed, or the optimality of the current solution is proved.","PeriodicalId":416196,"journal":{"name":"The Sharpest Cut","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132027741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Sharpest CutPub Date : 1900-01-01DOI: 10.1137/1.9780898718805.ch5
J. Fonlupt
{"title":"The Clique-Rank of 3-Chromatic Perfect Graphs","authors":"J. Fonlupt","doi":"10.1137/1.9780898718805.ch5","DOIUrl":"https://doi.org/10.1137/1.9780898718805.ch5","url":null,"abstract":"The clique-rank of a perfect graph G introduced by Fonlupt and Sebö is the linear rank of the incidence matrix of the maximum cliques of G. We study this rank for 3-chromatic perfect graphs. We prove that if, in addition, G is diamond-free, G has two distinct colorations. An immediate consequence is that the Strong Perfect Graph Conjecture holds for diamond-free graphs and for graphs with clique number equal to three. The proofs use both linear algebra and combinatorial arguments.","PeriodicalId":416196,"journal":{"name":"The Sharpest Cut","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116872107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}