Results 111 to 120 of about 6,090,423 (307)
On the dimension of partially ordered sets
Journal of Combinatorial Theory, Series A, 1977 AbstractA generalization of the concept of dimension of a poset, the stable dimension, is introduced, and it is shown that there is a simple procedure for determining its value. No such procedure is known for the dimension itself. The main theorem shows that the stable dimension is equal to the maximum number of elements in a pair of antichains of the ...
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Asymptotic enumeration of partially ordered sets [PDF]
Pacific Journal of Mathematics, 1980 The author define the entropy function S( ρ)=Lim n- ∞ 2n −2 lnN (n, ρ ), where N(n, ρ ) is the number of distinct partial order relations which may be defined on a set of n elements such that a fraction ρ of the possible n(n−1)/2 pairs are comparable.We derive upper bounds to S(ρ) to show that S(ρ) .699.
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Emerging experimental and computational methods for studying redox‐regulated structural transitions
FEBS Letters, EarlyView.Redox reactions can reshape proteins and alter how they behave in cells, with important consequences for health and disease. This review explores emerging experimental and computational approaches for discovering these redox‐sensitive protein switches, revealing their structural effects, and predicting their behavior, opening new opportunities to ...
Tasneem Rass +2 more
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Best Proximity Point for the Sum of Two Non-Self-Operators
Journal of Mathematics, 2020 In the present paper, we focus our attention on the existence of the fixed point for the sum of the cyclic contraction and the noncyclic accretive operator. Also, we study the best proximity point for the sum of two non-self-mappings.
V. Pragadeeswarar, R. Gopi, M. De la Sen
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The Redheffer Matrix of a Partially Ordered Set [PDF]
The Electronic Journal of Combinatorics, 2004 R. Redheffer described an $n\times n$ matrix of 0's and 1's the size of whose determinant is connected to the Riemann Hypothesis. We describe the permutations that contribute to its determinant and its permanent in terms of integer factorizations. We generalize the Redheffer matrix to finite posets that have a 0 element and find the analogous results ...
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‘Guide and Prejudice’— How Argonautes recognize targets across domains of life
FEBS Letters, EarlyView.Argonaute proteins use short nucleic‐acid guides to locate and regulate specific targets across all domains of life. Despite striking diversity—from human gene silencing to bacterial immune defence—all Argonautes share a conserved three‐stage recognition logic: guide‐directed sampling, progressive target pairing with a conformational checkpoint and ...
Jack P. K. Bravo
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An Arithmetical Theorem for Partially Ordered Sets [PDF]
, 1950 The simplest multiplicative systems in which arithmetical ideas can be defined are semigroups. For such systems irreducible (prime) elements can be introduced and conditions under which the fundamental theorem of arithmetic holds have been ...
Doyle, Worthie Lefler
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Structural and biochemical analysis of a B12 superbinder
FEBS Letters, EarlyView.BtuG proteins are vitamin B12 scavengers in Bacteroides thetaiotaomicron, a dominant human gut bacterium. We present crystal structures of three BtuG homologs bound to cobalamin and its precursor cobinamide, revealing picomolar binding affinities, among the highest known for any natural protein.
Jose M. Martinez Felices +3 more
wiley +1 more source
On Sums Over Partially Ordered Sets [PDF]
The Electronic Journal of Combinatorics, 1999 We establish a general theorem for reducing sums of type $\sum_{y\ge x} g(y)$ where $g$ is a mapping from a partially ordered set into an abelian group. Conclusions concern the Möbius function, the principle of inclusion-exclusion, the Tutte polynomial and Crapo's beta invariant.
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FEBS Letters, EarlyView.Mycobacterial 3‐methylcrotonyl‐CoA carboxylase uses a mobile biotin‐carrying domain to shuttle a carboxyl group between two catalytic sites, enabling carboxylation of 3‐methylcrotonyl‐CoA during leucine breakdown. Cryo‐electron microscopy captures the carrier at both sites and reveals an inward loop movement that may prevent futile rebinding to the ...
Ajit Yadav +2 more
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