It is well-known that Independence Friendly (IF) logic is equivalent to existential second-order logic (Σ 1) and, therefore, is not closed under classical negation. The boolean closure of IF sentences, called Extended IF-logic, on the other hand, corresponds to a proper fragment of ∆2. In this paper we consider IF-logic extended with Hodges’ flattening operator, which allows classical negation ...

Oscillations in a power system can be categorized into free oscillations and forced oscillations. Many algorithms have been developed to estimate the modes of free oscillations in a power system. Recently, forced oscillations caught many attentions. Techniques are proposed to detect forced oscillations and locate their sources. In addition, forced oscillations may have negative impact on the es...

polygroups are multivalued systems that satisfy group like axioms. in this paper the class of n-arypolygroups is introduced. the concepts of n-ary normal subpolygroups and strong homomorphisms of n-arypolygroups are adopted. with respect to these concepts the isomorphism theorems for n-ary polygroups arestated and proved. finally, we will consider the fundamental relation  * defined on an n-ar...

In this paper, we introduce a new skewed distribution of which normal and power normal distributions are two special cases. This distribution is obtained by taking geometric maximum of independent identically distributed power normal random variables. We call this distribution as the power normal--geometric distribution. Some mathematical properties of the new distribution are presented. Maximu...

semen hyperviscosity (shv) is one of the factors involved in deficiency in sperm function. this research aimed to evaluate seminal plasma total antioxidant capacity (tac) and malondialdehyde (mda) levels in infertile patients with hyperviscous and non-hyperviscous semen samples to understand whether hyperviscous semen is associated with oxidative damage in infertile subjects. in this cross sect...