Results 271 to 280 of about 34,321,194 (310)

(g, f)-Factors and [a, b]-Factors

2011
In this chapter we investigate (g, f)-factors and [a, b]-factors, which are natural generalizations of f-factors and regular factors, respectively. We first give a criterion for a graph to have a (g, f)-factor, which is called the (g, f)-factor theorem. Then we obtain some sufficient conditions for graphs to have (g, f)- factors and [a, b]-factors.
Jin Akiyama, Mikio Kano
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Dimers of Escherichia coli F′ factors

Biochemical and Biophysical Research Communications, 1973
Abstract Covalently closed circular DNA dimers of several E. coli sex factors have been isolated. One of these, F′451, a dimer of F′450, has a molecular weight of ca. 230 × 10 6 daltons. F′451 (λ) containing a λ prophage has a molecular weight of 260 × 10 6 and is probably the largest covalent closed circle of DNA yet reported ...
A, Folkmanis, D, Freifelder
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Fractional ( g, f )-factors of graphs

Acta Mathematica Scientia, 2001
Using graphical methods, the authors present a new proof of a characterization of the existence of fractional \((g,f)\)-factors of a multigraph. Based on their proof, a polynomial algorithm for finding a \((g,f)\)-factor can be described.
Liu, Guizhen, Zhang, Lanju
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Transfer inhibition of RP4 by F factor

Molecular and General Genetics MGG, 1983
When RP4 and F factors were brought together into one E. coli cell, the F factor reduced 500-1000-fold the frequency of transfer of RP4. However, F had almost no effect on the surface exclusion and pilus formation by RP4. In contrast, RP4 did not affect the transfer of F.
K, Tanimoto, T, Iino
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Two-dimensional tunnel heading stability factors F, F and F

Tunnelling and Underground Space Technology, 2020
Abstract This paper investigates the use of stability factors to estimate tunnel heading pressures. The primary method adopted is a conventional equation based on the soil property and stability factors, analogous to the bearing capacity factors (Nc, Ns and Nγ) of strip footings.
Shiau, Jim, Al-Asadi, Fadhil
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\(F\)-factor and vertex-disjoint \(F\) in a graph.

Ars Comb., 2003
Let \(F\) be the graph obtained from \(K_4\) by removing two edges with a common vertex, and for a graph \(G\), let \(\sigma _2(G)\) denote the minimum degree sum of a pair of nonadjacent vertices. The paper proves that a graph \(G\) with \(4k\) vertices and \(\sigma _2(G)\geq 5k\) has an \(F\)-factor.
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Isolated Toughness and Existence of f-Factors

2007
Let G be a graph with vertex set V (G) and edge set E(G). The isolated toughness of G is defined as I(G) = min{|S|/i(G-S) | S ⊆ V (G), i(G-S) = 2} if G is not complete; otherwise, set I(G) = |V (G)|- 1. Let f and g be two nonnegative integer-valued functions defined on V (G) satisfying a ≤ g(x) ≤ f(x) ≤ b.
Yinghong Ma, Qinglin Yu
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Perfect \(f\)-matchings and \(f\)-factors in hypergraphs -- a combinatorial approach

Discret. Math., 2017
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Isabel Beckenbach, Robert Scheidweiler
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Restriction of bacteriophage φX174 by F factor

Biochemical and Biophysical Research Communications, 1969
Abstract Bacteriophage φX174 is restricted in F+ cells of Escherichia coli C. Restriction is causally linked to the acquisition of the episome and is lost on its removal. Phage produced in the restrictive host is not modified. Restriction occurs at some stage beyond adsorption and eclipse but does not appear to be due to a defect in phage ...
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Some conditions for the existence of f‐factors

Journal of Graph Theory, 1985
AbstractLet m, l, n be three odd integers such that m > l > n. It is proved that if a graph G has an m‐factor and an n‐factor, then it also has an l‐factor. In addition, we obtain sufficient conditions for the existence of an f‐factor, in terms of vertex‐deleted subgraphs.
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