113 research outputs found
Fixed point results for nonexpansive mappings on metric spaces
In this paper we obtain some fixed point results for a class of nonexpansive single-valued mappings and a class of nonexpansive multi-valued mappings in the setting of a metric space. The contraction mappings in Banach sense belong to the class of nonexpansive single-valued mappings considered herein. These results are generalizations of the analogous ones in Khojasteh et al. [Abstr. Appl. Anal. 2014 (2014), Article ID 325840]
F-contractions of Hardy–Rogers type and application to multistage decision
We prove fixed point theorems for F-contractions of Hardy–Rogers type involving self-mappings defined on metric spaces and ordered metric spaces. An example and an application to multistage decision processes are given to show the usability of the obtained theorems
Irreducibility of Hurwitz spaces of coverings with monodromy groups Weyl groups of type W(B_d)
Let Y be a smooth, connected, projective complex curve of genus ≥0. R. Biggers and M. Fried [J. Reine Angew. Math. 335, 87–121 (1982; Zbl 0484.14002), Trans. Am. Math. Soc. 295, No. 1, 59–70 (1986; Zbl 0601.14022)] proved the irreducibility of the Hurwitz spaces which parametrize coverings of ℙ 1 whose monodromy group is a Weyl of type W(D d ). Here we prove the irreducibility of Hurwitz spaces that parametrize coverings of Y with monodromy group a Weyl group of type W(B d )
Fixed point results for ordered S-G-contractions in ordered metric spaces
In this paper, we prove existence and uniqueness of fixed point in the setting of ordered metric spaces. Precisely, we combine the recent notions of (F,φ)-contraction and Z-contraction in order to introduce the notion of ordered S-G-contraction. Then we use the notion of ordered S-G-contraction to show existence and uniqueness of fixed point. We stress that the notion of ordered S-G-contraction includes different types of ordered contractive conditions in the existing literature. Also, we give some examples and additional results in ordered partial metric spaces to support the new theory
On Hurwitz spaces of coverings with one special fiber
Let X ! X0 f ! Y be a covering of smooth, projective complex curves such that is a degree 2 étale covering and f is a degree d covering, with monodromy group Sd, branched in nC 1 points one of which is a spe- cial point whose local monodromy has cycle type given by the partition eD.e1;:::; er/ of d. We study such coverings whose monodromy group is either W.Bd/ or w N.W.Bd//.G1/w 1 for some w2 W.Bd/, where W.Bd/ is the Weyl group of type Bd, G1 is the subgroup of W.Bd/ generated by reflections with respect to the long roots "i " j and N.W.Bd//.G1/ is the normalizer of G1. We prove that in both cases the corresponding Hurwitz spaces are not connected and hence are not irreducible. In fact, we show that if nCjej 2d, wherejejD Pr iD1.ei 1/, they have 2 2g 1 connected components
From Caristi's Theorem to Ekeland's Variational Principle in -Complete Metric-Like Spaces
We discuss the extension of some fundamental results in nonlinear analysis to the setting of0σ-complete metric-like spaces. Then, we show that these extensions can be obtained via the corresponding results in standard metric spaces
Irreducibility of Hurwitz spaces of covering of an elliptic curve of prime degree with one point of total ramification
Let Y be an elliptic curve, p a prime number and WH_{p,n}(Y) the Hurwitz space that parametrizes equivalence classes of p-sheeted branched coverings of Y , with n branch points, n − 1 of which are points of simple ramification and one of total ramification.In this paper, we prove that WH_{p,n}(Y) is irreducible if n − 1≥ 2 p
An alternative and easy approach to fixed point results via simulation functions
Abstract
We discuss, extend, improve and enrich results on simulation functions established by several authors. Furthermore, by using Lemma 2.1 of Radenovic et al. [Bull. Iran. Math. Soc., 2012, 38, 625],we get much shorter and nicer proofs than the corresponding ones in the existing literature
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