This paper is dedicated to the spectral optimization problem $$ \mathrm{min}\left\{\lambda_1^s(\Omega)+\cdots+\lambda_m^s(\Omega) + \Lambda \mathcal{L}_n(\Omega)\colon \Omega\subset D \mbox{ s-quasi-open}\right\} where $\Lambda>0, D\subset \mathbb{R}^n$ a bounded open set and $\lambda_i^s(\Omega)$ $i$-th eigenvalues of fractional Laplacian on $\Omega$ with Dirichlet boundary condition $\mathbb{...

The purpose of this paper is to prove that every sequence of closed approximable measures defined on the Borelfield of a normal topological space with values in an abelian topological group is Cauchy convergent for all Borel sets if it is Cauchy convergent for all regular open sets. In particular every sequence of measures on the Borel-field of a perfectly normal topological space which is Cauc...

In this paper, countable compactness and the Lindel¨of propertyare defined for L-fuzzy sets, where L is a complete de Morgan algebra. Theydon’t rely on the structure of the basis lattice L and no distributivity is requiredin L. A fuzzy compact L-set is countably compact and has the Lindel¨ofproperty. An L-set having the Lindel¨of property is countably compact if andonly if it is fuzzy compact. ...

A new class of functions, called Intuitionistic fuzzy π-generalized π-closed set is introduced. Basic properties of Intuitionistic fuzzy π-generalized π-closed set are studied. MSC: 68T27 • 68T37

In this state-of-the-art paper, important advances that have been made during the past five years for both general and interval type-2 fuzzy sets and systems are described. Interest in type-2 subjects is worldwide and touches on a broad range of applications and many interesting theoretical topics. The main focus of this paper is on the theoretical topics, with descriptions of what they are, wh...

In this paper, a condition which ensures the existence of fuzzy simply open sets in $P$- space is obtained. It established that disjoint $G_{\delta}$-sets $P$-space are cs dense sets. A for strongly irresolvable and globally disconnected to become hyperconnected D-Baire space. obtained extremally disconnected, semi-$P$ does not have $G_{\delta}$-sets.

in this work, we define a fuzzy soft set theory and its related properties. we then define fuzzy soft aggregation operator that allows constructing more efficient decision making method. finally, we give an example which shows that the method can be successfully applied to many problems that contain uncertainties.