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159 results on '"Gobel, F."'

5. Problem 68-1

Author

Gobel, F. and Carlitz, L.

Published
1969

7. Spanning trees with pairwise nonadjacent endvertices

Author

Böhme, T., Bohme, T., Broersma, Haitze J., Gobel, F., Kostochka, A.V., Stiebitz, M., and Discrete Mathematics and Mathematical Programming

Subjects
Discrete mathematics, Spanning tree, Trémaux tree, Spanning tree with pairwise nonadjacent endvertices, Tree (graph theory), Depth-first-search tree, Simplex graph, IR-30145, Theoretical Computer Science, Combinatorics, Edge-transitive graph, Graph power, Discrete Mathematics and Combinatorics, METIS-140784, Graph factorization, Complement graph, MathematicsofComputing_DISCRETEMATHEMATICS, Mathematics
Abstract

A spanning tree of a connected graph G is said to be an independency tree if all its endvertices are pairwise nonadjacent in G. We prove that a connected graph G has no independency tree if and only if G is a cycle, a complete graph or a complete bipartite graph the color classes of which have equal cardinality.

Published
1997
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9. Generating all 3-connected 4-regular planar graphs from the octahedron graph

Author

Broersma, Haitze J., Duijvestijn, A.J.W., Gobel, F., and Discrete Mathematics and Mathematical Programming

Subjects
Discrete mathematics, Book embedding, Symmetric graph, IR-70999, Computer Science::Computational Geometry, 1-planar graph, Planar graph, Combinatorics, symbols.namesake, Pathwidth, Chordal graph, Outerplanar graph, symbols, METIS-140354, Mathematics::Metric Geometry, Discrete Mathematics and Combinatorics, Geometry and Topology, Pancyclic graph, Mathematics
Abstract

We prove that all 3-connected 4-regular planar graphs can be generated from the Octahedron Graph, using three operations. We generated these graphs up to 15 vertices inclusive. Moreover, by including a fourth operation we obtain an alternative to a procedure by Lehel to generate all connected 4-regular planar graphs from the Octahedron Graph.

Published
1993
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10. Hoede-sequences

Author

Gobel, F.

Subjects
EWI-3411, MSC-05A15, MSC-05A18, MSC-05A16, IR-65778
Abstract

In an attempt to prove the double-cycle-conjecture for cubic graphs, C. Hoede formulated the following combinatorial problem. “Given a partition of {1, 2, . . . , 3n} into n equal classes, is it possible to choose from each class a number such that these numbers form an increasing sequence of alternating parity?��? Let a Hoede-sequence be defined as an increasing sequence of natural numbers of alternating parity. We determine the average number of Hoede-sequences w.r.t. arbitrary partitions, and obtain bounds for the maximum and minimum number of Hoede-sequences w.r.t. partitions into equal classes.

Published
2001

11. Z-related pairs in microtonal systems

Author

Althuis, T.A. and Gobel, F.

Subjects
MSC-05B99, METIS-141189, EWI-3344, IR-65712
Abstract

Various infinite families of Z-related pairs in microtonal systems are presented. Soderberg's dual inversion is compared to a more special transformation, the one-pitch shift. The material is illustrated by several examples.

Published
2000

14. Cyclic graphs

Author

Gobel, F., Neutel, E.A., and Discrete Mathematics and Mathematical Programming

Subjects
Circulant, Diameter, Ádám isomorphism, Line-transitive, Computer Science::Formal Languages and Automata Theory
Abstract

A subclass of the class of circulant graphs is considered. It is shown that in this subclass, isomorphism is equivalent to Adam-isomorphism. Various results are obtained for the chromatic number, line-transitivity and the diameter.

Published
1996

21. The L-shaped dissection problem

Author

Gobel, F.

Subjects
Tessellations (Mathematics) -- Tests, problems and exercises, Partitions (Mathematics) -- Tests, problems and exercises, Number theory -- Tests, problems and exercises, Mathematics
Published
1991

31. Delayed progression of atherosclerosis in coronary bypass grafts is similar in women compared to men following aggressive cholesterol lowering despite more frequent risk factors: post CABG trial

Author

Campeau, L., primary, Knatterud, G., additional, Domanski, M., additional, Forrester, J.S., additional, Geller, N., additional, Gobel, F., additional, Herd, J.A., additional, Hoogwerf, B., additional, Hunninghake, D.B., additional, White, C., additional, and Rosenberg, Y., additional

Published
1998
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35. The effect of comorbidity on use of thrombolysis or aspirin in patients with acute myocardial infarction eligible for treatment.

Author

McLaughlin, Thomas J., Soumerai, Stephen B., Willison, Donald J., Gurwitz, Jerry H., Gao, Xiaoming, Borbas, Catherine, Gobel, Fredarick, McLaughlin, T J, Soumerai, S B, Willison, D J, Gurwitz, J H, Gao, X, Borbas, C, and Gobel, F

Subjects
ASPIRIN, PLATELET aggregation inhibitors, COMPARATIVE studies, CONFIDENCE intervals, DECISION making, LONGITUDINAL method, RESEARCH methodology, MEDICAL cooperation, MEDICAL protocols, MYOCARDIAL infarction, RESEARCH, RESEARCH funding, THROMBOLYTIC therapy, COMORBIDITY, LOGISTIC regression analysis, EVALUATION research, RETROSPECTIVE studies, PATIENT selection, ODDS ratio, THERAPEUTICS
Abstract

Objective: Growing evidence indicates that life-sustaining therapies for the treatment of acute myocardial infarction (AMI) are underused among patients eligible for therapy, including the elderly and women. We examined the effect of a patient's comorbidity burden on use of these highly effective therapies in eligible populations of individuals with AMI.Design: Retrospective cohort design.Setting and Patients: We reviewed the medical records of 2,409 individuals at 37 Minnesota hospitals from October 1992 through July 1993 with an admission diagnosis of AMI, suspected AMI, or rule-out AMI, who met electrocardiographic, laboratory, and clinical criteria for AMI.Measurements and Main Results: Using multivariate logistic regression models, we determined the association between a validated comorbidity measure and the proportion of eligible patients who received thrombolysis or aspirin. Controlling for other factors previously reported to influence rates of study treatment, the odds of receipt of thrombolysis among patients with severe comorbidity was 0.49 (95% confidence interval [CI] 0.27, 0.88) when compared with individuals without such limitation. Similarly, the odds of aspirin treatment among study patients with severe comorbidity was 0.46 (95% CI 0.30 0.72), compared with individuals without severe comorbidity. We did not distinguish any differences in patterns of treatment with either study treatment among patients with mild or moderate comorbidity when compared with individuals without any concomitant comorbidity.Conclusions: This study indicates that patients with severe mental and physical comorbidities are less likely to receive standard therapies for AMI recommended in national treatment guidelines. [ABSTRACT FROM AUTHOR]

Published
1997
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