The Upper Cretaceous Sudr Formation at Wadi El Dakhl, West Gulf of Suez (Northeast Egypt) has been described to analyze
the facies and their cycles in conjunction with the influence of sea level and tectonics. The Sudr Formation (~ 130 m thick) is
composed mainly of chalk and chalky limestone, with intercalations of argillaceous limestone and marl. It could be divided
into two members; the Markha of the early–middle Campanian age and Abu Zenima of the late Campanian–Maastrichtian
age. Biostratigraphically, nine planktonic foraminiferal zones have been recorded which encompass the studied section.
Petrographic studies of the Sudr Formation led to identifying five facies types; four carbonate facies and one marl facies. These
facies have been deposited in the environmental conditions of an inner, middle, outer shelf, and open marine basinal setting.
Two types of cyclicity have been identified: shallowing-upward and deepening-upward cycles which indicate a change in
oscillation in the relative sea level. The comparison of the studied sea-level curve with the global curves of Haq et al. (Science 365:1156–1167, 1987) and Haq (Glob Planet Change 113:44–58, 2014) refer to general correspondence between them
in addition to the clear effect of the tectonic events that influenced the obtained sea-level curve of the present study. Three
pronounced tectonic events that impacted the deposition of the studied Sudr Formation were recorded. These tectonics were
operated during the late Santonian, middle Campanian, and late Maastrichtian time intervals. These tectonics are most probably related to the collision of African/Arabian and Eurasia Plates.

In the present paper, a characterization of the intuitionistic fuzzy sets, the interval-valued intuitionistic fuzzy sets and their set-operations are given. By making use of these characterizations, the relationships between the interval-valued intuitionistic fuzzy topology and four fuzzy topologies associated with it are studied. For this reason, some subclasses of the family of interval-valued intuitionistic fuzzy topologies on a set that we call pre-suitable and suitable are introduced. Furthermore, the concepts of homeomorphism functions and compactness in the framework of interval-valued intuitionistic fuzzy topological spaces are introduced and studied. Keywords: Interval-valued intuitionistic fuzzy set, interval-valued intuitionistic fuzzy topology, fuzzy topology, homeomorphism, compactness

© 2021 – IOS Press.

DOI: 10.3233/JIFS-202757

The concepts of ij -δ-semi closed and ij -δ-semi open sets in bitopological spaces are introduced and studied. Also, the notions of    sets and    sets are investigated. Furthermore, a new closure operator called  on the bitopological space  is defined and associated topology   is given.

@2021 by the authors.

http://doi.org/10.26637/mjm0903/008

In this paper, we define r-L-fuzzy closed convex sets and r-L-fuzzy closed neighbourhoods in an (L, M)-fuzzy topology (L, M)-fuzzy convexity spaces. Also, r-L-fuzzy neighbourhood separation properties rL-FNS_i were studied where . In addition, we also study the invariance or otherwise of these separation properties under subspace and product. @FMI

@ 2021 Research Institute for Basic Science, Wonkwang University

http://www.afmi.or.kr

 https://doi.org/10.30948/afmi.2021.21.1.93

In this paper, we point out that the proof of Theorem 2.4(5), Proposition 2.6(1) and Proposition 2.8(1) in the paper titled ”On (L, M)-fuzzy convex structures” (Filomat 33(13): 4151-4163, 2019) are not true in general. Then, we give three correct proofs of these results.

@ 2021 Faculty of Sciences and Mathematics, University of NIŠ, Serbia.

http://www.pmf.ni.ac.rs/filomat

Different from the separation axioms in the framework of (L, M)-fuzzy convex spaces defined by Liang et al. (2019). In this paper, we give some new investigations on separation axioms in (L, M)-fuzzy convex structures by L-fuzzy hull operators and r-L-fuzzy biconvex. We introduce the concepts of r-LFS_i spaces where  , and obtain various properties. In particular, we discuss the invariance of these separation properties under subspace and product.

DOI:10.3233/JIFS-200340

© 2021 – IOS Press.                                                 

In this paper, we introduce the concepts of delta generalized closed, generalized delta closed and delta star generalized closed sets in bitopological spaces and study some of its properties and its relations with other types of closed sets. Also, we study some properties of weak forms of separation axioms.

© 2021 Pushpa Publishing House, Prayagraj, India.

http://www.pphmj.com

http://dx.doi.org/10.17654/UM014010013