Copyright q 2011 ChiMing Chen. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We obtain some new fixed point theorems for a ψ, φ-pair Meir-Keeler-type set-valued contraction map in metric spaces. Our main results generalize and i...

*Correspondence: [email protected] Department of Mathematics, Hashemite University, Zarqa, Jordan Abstract In this paper, we prove some quadruple coincidence and quadruple common fixed point theorems for F : X4 → X and g : X → X satisfying (φ –ψ ) contractions in partially ordered G-metric spaces. We illustrate our results based on an example of the main theorems. Also, we deduce quadruple coi...

Let A and B be Banach algebras with bounded approximate identities let Φ:A→B a surjective continuous linear map which preserves two-sided zero products (i.e., Φ(a)Φ(b)=Φ(b)Φ(a)=0 whenever ab=ba=0). We show that Φ is weighted Jordan homomorphism provided product determined weakly amenable. These conditions are in particular fulfilled when the group algebra L1(G) G any locally compact group. also...

A (projective) manifoldX of dimension 2n+1 together with a subbundle F ⊂ TX of rank 2n is a contact manifold if the pairing F × F → TX/F =: L defined by the Lie bracket is everywhere non-degenerate. An alternative description is as follows: there is a (sub-)line bundle L ⊂ ΩX such that the induced contact form θ ∈ H(X,ΩX⊗L) is non-degenerate in the sense that in local coordinates the form θ ∧ (...