Cellular lamellipodia bind to the matrix and probe its rigidity through forces generated by rearward F-actin transport. Cells respond to matrix rigidity by moving toward more rigid matrices using an unknown mechanism. In spreading and migrating cells we find local periodic contractions of lamellipodia that depend on matrix rigidity, fibronectin binding and myosin light chain kinase (MLCK). Thes...

Tutte’s Wheels-and-Whirls Theorem is a basic inductive tool for dealing with 3-connected matroids. This paper proves a generalization of that theorem for the class of 2-polymatroids. Such structures include matroids, and they model both sets of points and lines in a projective space and sets of edges in a graph. The main result proves that, in a 3-connected 2-polymatroid that is not a whirl or ...

state conditions under which there exist solutions to x = f(x) for the singlevalued function f or to Y E F(y ) for the set-valued mapping F. The prototype of the former is the contraction mapping theorem, while that of the latter is the Kakutani fixed point theorem. These results, as well as generalizations, applications, and other references, are surveyed in [ 14 ]. A representative sample of ...

A graph operation that contracts edges is one of the fundamental operations in theory minors. Parameterized Complexity editing to a family graphs by contracting k has recently gained substantial scientific attention, and several new results have been obtained. Some important families graphs, namely, subfamilies chordal context edge contractions, proven be significantly difficult than might expe...

Let CMSO denote the counting monadic second order logic of graphs. We give a constructive proof that for some computable function f , there is an algorithm A that takes as input a CMSO sentence φ, a positive integer t, and a connected graph G of maximum degree at most ∆, and determines, in time f(|φ|, t) · 2O(∆·t) · |G|O(t), whether G has a supergraph G′ of treewidth at most t such that G′ |= φ...

The purpose of this paper is to study the strong convergence theorems of Moudafi's viscosity approximation methods for a nonexpansive mapping T in CAT(0) spaces without the property P. For a contraction f on C and t ∈ (0, 1), let x t ∈ C be the unique fixed point of the contraction x → tf (x) ⊕ (1 – t)Tx; i.e., x t = tf (x t) ⊕ (1 – t)Tx t and x n+1 = α n f (x n) ⊕ (1 – α n)Tx n , n ≥ 0, where ...

When a function f is monotonic w.r.t. x in a given box, it is well-known that the monotonicity-based interval extension of f computes a sharper image than the natural interval extension does. Indeed, the overestimation due to the variable x with multiple occurrences in f disappears. However, monotonicity has not been exploited in interval filtering/contraction algorithms for solving systems of ...