جستجوی مقالات مرتبط با کلیدواژه « حاصلضرب دکارتی » در نشریات گروه « ریاضی »

In this paper, we study the definitions of ordered pair from the point of view of Kuratowski, Wiener, Hausdorff and Morse. We first present the possible definitions of an ordered pair, and then examine the structure of the Cartesian product of sets, relations, and functions. This paper can be useful for mathematical researchers in creating new insight and better understanding of the concept of ordered pair and its related mathematical concepts, such as ordered and unordered Cartesian product, relation and function, etc.

In this paper we will give the definition of almost multiplicative linear functionals on commutative Banach algebras and investigate the closeness of these linear functionals with multiplicative linear functionals (AMNM property) . Several Banach algebra has this property, but not all of them. Due to relationship between the spectrum of an element of a complex Banach algebra and multiplicative linear functionals. Thus this investigation about almost multiplicative linear functionals give us some information about the spectrum of an element of a Banach algebra. In this paper We will give a very helpful theorem, for this investigation. Also we will show that, if in two commutative Banach algebras A and B, near any almost multiplicative linear functional, there is a multiplicative linear functional, then A×B also has this property and vice versa. We investigate this property for finite product of commutative Banach algebras. Also we will refer to some of the sequential spaces.