Search results for "Matematica"

A note on boundary conditions for nonlinear operators

2008

We investigate boundary conditions for strict-$\psi$-contractive and $\psi$-condensing operators. We derive results on the existence of eigenvectors with positive and negative eigenvalues and we obtain fixed point theorems for classes of noncompact opera\-tors.

Eigenvectors of k-psi-contractive wedge operators

2008

We present new boundary conditions under which the fixed point index of a strict-$\psi$-contractive wedge operator is zero. Then we investigate eigenvalues and corresponding eigenvectors of k-$\psi$-contractive wedge operators.

On fixed points of alpha-eta-psi-contractive multifunctions

2014

Recently Samet et al. [B. Samet, C. Vetro, P. Vetro, Fixed point theorem for alpha-psi-contractive type mappings, Nonlinear Anal., 75 (2012), 2154{2165] introduced the notion of alpha-psi-contractive type mappings and established some fixed point theorems in complete metric spaces. Succesively, Asl et al. [J.H. Asl, SH. Rezapour, N. Shahzad, On fixed point of alpha-contractive multifunctions, Fixed Point Theory Appl., 2012, 212 (2012)] introduced the notion of alpha_*-psi-contractive multifunctions and give a fixed point result for these multifunctions. In this paper we obtain certain new fixed point and common fixed point theorems via alpha_*-admissible multifuncions with respect to eta. T…

MR3029186 Reviewed Kuo, Wen-Chi; Vardy, Jessica Joy; Watson, Bruce Alastair Mixingales on Riesz spaces. J. Math. Anal. Appl. 402 (2013), no. 2, 731–7…

2013

Decomposability in the space of HKP-integrable functions

2014

In this paper we introduce the notion of decomposability in the space of Henstock-Kurzweil-Pettis integrable (for short HKP-integrable) functions. We show representations theorems for decomposable sets of HKP-integrable or Henstock integrable functions, in terms of the family of selections of suitable multifunctions.

A decomposition of Denjoy-Khintchine-Pettis and Henstock-Kurzweil-Pettis integrable multifunctions

2010

We proved in one of our earlier papers that in case of separable Banach space valued multifunctions each Henstock-Kurzweil-Pettis integrable multifunction can be represented as a sum of one of its Henstock-Kurzweil-Pettis integrable selector and a Pettis integrable multifunction. Now, we prove that the same result can be achieved in case of an arbitrary Banach space. Moreover we show that an analogous result holds true also for the Denjoy-Khintchine-Pettis integrable multifunctions. Applying the representation theorem we describe the multipliers of HKP and DKP integrable functions. Then we use this description to obtain an operator characterization of HKP and DKP integrability.

MR3266136 Porcello, G., Decomposability in the space of HKP-integrable functions. Math. Nachr. 287 (2014), no. 14-15, 17331744. 26A39 (26E25 28B20 54…

2015

The notion of decomposability for families of Banach space valued functions is a certain kind of generalization of convexity. Decomposability is usually de- ned (in a space, or some subspaces, of measurable functions as the space of Bochner integrable or Pettis integrable functions) with respect to a -algebra of sets. In the paper under review the author introduces the notion of decom- posability for vector-valued functions integrable in Henstock sense. Since the Henstock-type integrals act only on intervals, the author modi es in a slight but essential way the classical"de nition of decomposability: instead of a - algebra of sets, one has to work with the ring A generated by the subinterva…

Ordinary (p_1,...,p_m)-Laplacian system with mixed boundary value

2016

In this paper we prove the existence of multiple weak solutions for an ordinary mixed boundary value system with (p_1,...,p_m)-Laplacian by using recent results of critical points.

Multiple solutions for a mixed boundary value problem

2010

MR2819034 Castillo, René Erlín The Nemytskii operator on bounded p-variation in the mean spaces. Mat. Enseñ. Univ. (N. S.) 19 (2011), no. 1, 31–41. (…

2012

The author introduces the notion of bounded $p$-variation in the sense of $L_p$-norm. Precisely: Let $f \in L_p[0,2\pi]$ with $1<p<\infty$. Let $P: 0=t_0 <t_1< \cdots <t_n=2\pi$ be a partion of $[0,2\pi]$ if $$V_p^m(f,T) = \sup \{\sum_{k=1} ^{n}\int_T\frac{|f(x+t_k)-f(x+t_{k-1})|^p)}{|t_k-t_{k-1}|^{p-1}}\}< \infty,$$ where the supremum is taken over all partitions $P$ of $[0,2\pi]$ and $T=\mathbb{R}/2\pi \mathbb{Z}$, then $f$ is said to be of bounded $p$-variation in the mean. The author obtains a Riesz type result for functions of bounded $p$-variation in the mean and gives some properties for functions of bounded $p$-variation by using the Nemytskii operator.