We discuss the temporal logic`USF', involving Until, Since and the xed point operator ' of Gabbay, with semantics over the natural numbers. We show that any formula not involving Until is equivalent to one without nested xed point operators. We then prove that USF has expressive power matching that of the monadic second-order logic S1S. The proof shows that any USF-formula is equivalent to one ...

Let Q IFP be any quantiier such that FO(Q IFP), rst order logic enhanced with Q IFP and its vectorizations, equals inductive xed point logic, IFP in expressive power. It is known that for certain quantiiers Q, the equivalence FO(Q IFP) IFP is no longer true if Q is added on both sides 12, 13]. Rather, we have FO(Q IFP ; Q) < IFP(Q) in such cases. We extend these results to a great variety of qu...

Let (x n) and (^ x n) be two vector sequences converging to a common limit. First, we shall deene nonlinear hybrid procedures which consist of constructing a new vector sequence (y n) with better convergence properties than (x n) and (^ x n). Then, this procedure is used for accelerating the convergence of a given sequence and applied to the construction of xed point methods. New methods are de...

Recently, Piri and Kumam [Fixed Point Theory and Applications 2014, 2014:210] improved concept of F -contraction and proved some Wardowski and Suzuki type …xed point results in metric spaces. The aim of this article is to de…ne generalized GF -contraction and establish Wardowski and Suzuki type …xed point results in metric and ordered metric spaces and derive main results of Piri et al. as coro...

in this paper, stochastic generalizations of some fixed point for operators satisfying random contractively generalized hybrid and some other contractive condition have been proved. we discuss also the existence of a solution to a nonlinear random integral equation in banah spaces.

In the 1920s, algebraic topology began to develop partially due to the need for new topological techniques in solving problems in xed point theory. Indeed, the celebrated Lefschetz xed point theorem is a far reaching generalization of the well-known Brouwer xed point theorem. The eld of topological xed point theory continued to ourish through the 1940s during which much of the foundations was l...

boujari [5] proved a fixed point theorem with an old version of the integraltype contraction , his proof is incorrect. in this paper, a new generalizationof integral type contraction is introduced. moreover, a fixed point theorem isobtained.

we consider the concept of ω-distance on a complete partially ordered g-metric space and prove some common fixed point theorems.

"This paper deals with some existence results for a class of implicit fractional q-difference equations. The are based on the fi xed point theory in Banach spaces and concept measure noncompactness. An illustrative example is given last section."

In this paper, we study the existence of solutions for fractional evolution equations with nonlocalconditions. These results are obtained using Banach contraction xed point theorem. Other resultsare also presented using Krasnoselskii theorem.