Search results for "Row and column spaces"

showing 3 items of 3 documents

A biproportional filter to compare technical and allocation coefficient variations

1997

International audience; In input-output analysis there are two alternate possibilities between Leontief's mechanism (fixed technical coefficients) and Ghosh's mechanism (fixed allocation coefficients). Testing the long term consistency of these mechanisms entails comparing input-output matrices over time. This paper challenges the value of proportional filters (separate comparison of column and row coefficients) and introduces the biproportional filter which allows simultaneous comparison of column and rows. An application is proposed using French input-output tables for 1980 and 1993. The stability of column coefficients cannot be taken for granted and generally, for any sector, both rows …

BiproportionSupply-drivenJEL: C - Mathematical and Quantitative Methods/C.C6 - Mathematical Methods • Programming Models • Mathematical and Simulation Modeling/C.C6.C67 - Input–Output ModelsChangeJEL: D - Microeconomics/D.D5 - General Equilibrium and Disequilibrium/D.D5.D57 - Input–Output Tables and AnalysisEnvironmental Science (miscellaneous)DevelopmentRow and column spacesStability (probability)Column (database)Consistency (statistics)Demand-drivenStatisticsComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATIONApplied mathematicsJEL : D - Microeconomics/D.D5 - General Equilibrium and Disequilibrium/D.D5.D57 - Input–Output Tables and Analysis[ SHS.ECO ] Humanities and Social Sciences/Economies and finances[SHS.ECO] Humanities and Social Sciences/Economics and FinanceMathematicsInput/outputJEL : C - Mathematical and Quantitative Methods/C.C6 - Mathematical Methods • Programming Models • Mathematical and Simulation Modeling/C.C6.C67 - Input–Output Models[SHS.ECO]Humanities and Social Sciences/Economics and FinanceTerm (time)Input-OutputFilter (video)RowRAS
researchProduct

Enumeration of L-convex polyominoes by rows and columns

2005

In this paper, we consider the class of L-convex polyominoes, i.e. the convex polyominoes in which any two cells can be connected by a path of cells in the polyomino that switches direction between the vertical and the horizontal at most once.Using the ECO method, we prove that the number fn of L-convex polyominoes with perimeter 2(n + 2) satisfies the rational recurrence relation fn = 4fn-1 - 2fn-2, with f0 = 1, f1 = 2, f2 = 7. Moreover, we give a combinatorial interpretation of this statement. In the last section, we present some open problems.

Discrete mathematicsRecurrence relationECO methodGeneral Computer SciencePolyominoGenerating functionRegular polygonRow and column spacesTheoretical Computer ScienceInterpretation (model theory)Generating functionsCombinatoricsSection (fiber bundle)Path (graph theory)Convex polyominoesComputer Science(all)MathematicsTheoretical Computer Science
researchProduct

Reducing the bandwidth of a sparse matrix with tabu search

2001

The bandwidth of a matrix { } ij a A = is defined as the maximum absolute difference between i and j for which 0 ≠ ij a . The problem of reducing the bandwidth of a matrix consists of finding a permutation of the rows and columns that keeps the nonzero elements in a band that is as close as possible to the main diagonal of the matrix. This NP-complete problem can also be formulated as a labeling of vertices on a graph, where edges are the nonzero elements of the corresponding symmetrical matrix. Many bandwidth reduction algorithms have been developed since the 1960s and applied to structural engineering, fluid dynamics and network analysis. For the most part, these procedures do not incorpo…

Mathematical optimizationInformation Systems and ManagementGeneral Computer ScienceBandwidth (signal processing)Management Science and Operations ResearchRow and column spacesMain diagonalIndustrial and Manufacturing EngineeringTabu searchDistance matrixModeling and SimulationCuthill–McKee algorithmMetaheuristicAlgorithmSparse matrixMathematicsEuropean Journal of Operational Research
researchProduct