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A graph H is a square root of a graph G if G can be obtained from H by the addition of edges between any two vertices in H that are of distance 2 from each other. The Square Root problem is that of deciding whether a given graph admits a square root. We consider this problem for planar graphs in the context of the " distance from triviality " framework. For(More)
A graph H is a square root of a graph G, or equivalently, G is the square of H, if G can be obtained from H by adding an edge between any two vertices in H that are of distance 2. The Square Root problem is that of deciding whether a given graph admits a square root. The problem of testing whether a graph admits a square root which belongs to some specified(More)
This study was designed to establish if clinical examination can accurately predict intraabdominal pressure (IAP). Between August 1998 and March 2000 a prospective blinded observational study of postoperative intensive care unit patients was undertaken at a major trauma center. IAP was measured using an intravesicular technique and compared with clinical(More)
OBJECTIVE To measure immunization coverage among children aged 12-23 months in Papua New Guinea (PNG) and to assess if and why there are differences between hard-to-reach and more accessible communities. METHODS WHO cluster sampling methodology was employed to measure immunization coverage in PNG's four regions. Survey data were re-analyzed according to a(More)
A homomorphism from a graph G to a graph H is a vertex mapping f from the vertex set of G to the vertex set of H such that there is an edge between vertices f (u) and f (v) of H whenever there is an edge between vertices u and v of G. The H-Colouring problem is to decide if a graph G allows a homomorphism to a fixed graph H. We continue a study on a variant(More)
L Tabár*, SW Duffy†, B Viták‡, H-H Chen§ and UB Krusemo# *Department of Mammography, Central Hospital, Falun, Sweden; †Biostatistics Unit, Medical Research Council, Cambridge, UK; ‡Department of Medical Radiology, University Hospital of Linköping, Linköping, Sweden; §Institute of Epidemiology, College of Public Health, National Taiwan University, Taipei,(More)
The problem of finding a disconnected cut in a graph is NP-hard in general but polynomial-time solvable on planar graphs. The problem of finding a minimal disconnected cut is also NP-hard but its computational complexity is not known for planar graphs. We show that it is polynomial-time solvable on 3-connected planar graphs but NP-hard for 2-connected(More)