We learn sets and their properties in Set Theory, a part of mathematical logic. A set is a collection of objects or a group of objects. Set elements or individuals are terms used to describe these entities. For example, a group of cricket players is a group of players.
Because a cricket team can only have 11 players at any given moment, we can claim that this set is finite. However, many sets, such as a set of n natural numbers, a set of whole numbers, a set of real numbers, a set of imaginary numbers, and so on, have infinite members.
Origins of Set Theory
Georg Cantor (1845-1918), a German mathematician, was the first to propose the concept of ‘Set Theory.’ He came upon sets while studying on “Problems on Trigonometric Series,” which has since become the most fundamental notions in mathematics. It will be impossible to explain other ideas such as relations, functions, sequences, probability, geometry, and so on without first comprehending sets.
Sets are defined as:
A set is a well-defined collection of objects or people, as we learnt in the introduction. Many real-life instances of sets include the number of rivers in India, the number of colours in a rainbow, and so on.
BOUNDES SETS:
1. Conceptualization
In several disciplines of mathematics, the term ‘bounded’ has multiple meanings. Bornological set is a comprehensive axiomatic approach to boundedness. We’ve compiled a collection of definitions in a variety of fields.
2. Definition in metric spaces
Consider E to be a metric space. A subset BE is bounded if there is a real number r for which d(x,y) all bounded sets of a quasigauge space (and thus of the more specific forms of spaces above) define a bornology on its underlying set.
3. Vector spaces with topological topologies
Let E be an LCTVS in definition 3.1. When UE is in the neighbourhood of 0, a subset BE is bounded if there is some real integer r such that B rU.
A bornology on an LCTVS’s underlying set is defined as its family of all bounded sets.
If a subset S of a partially ordered set P has both an upper and lower bound, or is contained in an interval, it is called bounded. It’s worth noting that this is a property of both the set S and the set S as a subset of P.
A bounded poset P (that is, one that has a least and greatest element by itself, not as a subset) is one that has the least and greatest element. It’s worth noting that boundedness has nothing to do with size, so a subset S of a bounded poset P with the order restriction on P isn’t necessarily a bounded poset.
If and only if it is bounded as a subset of Rn with the product order, a subset S of Rn is bounded with regard to the Euclidean distance. However, with respect to the lexicographical order, S can be bounded as a subset of Rn, but not with respect to the Euclidean distance.
When given any ordinal, there will always be some element of the class greater than it, a class of ordinal numbers is said to be unbounded, or cofinal. In this example, “unbounded” means unbounded as a subclass of the class of all ordinal numbers, rather than unbounded in and of itself.
UNBOUNDES SETS:
The phrases “bounded” and “unbounded” have a different meaning in functional analysis. Operators can be both bounded and unbounded. These operators differ from one another and are frequently incompatible with bounded for function definitions.
An unbounded operator is defined as “a mapping A from a set M in a topological vector space X onto a topological vector space Y so that there is a bounded set N M whose image A(N) is an unbounded set in Y,” according to Springer Online Reference Works’ Encyclopaedia of Mathematics.
You can have a set of numbers that is both bounded and unbounded. This definition is significantly more straightforward, yet it retains the same meaning as the previous two. A bounded set of numbers is one that has both an upper and lower bound.
Because it has a finite value at both ends, the interval [2,401] is a bounded set. You might also have a collection of constrained numbers like this: 1,1/2,1/3,1/4…, Unbounded sets have the opposite properties; their upper and/or lower limits are not finite.
Conclusion:
The properties of associativity and commutativity apply to operations such as union and intersection in set theory, just as they do to addition and multiplication in algebra. In addition, the union of sets distributes over the intersection of sets.
Sets are being used to describe functions, which are among the most important ideas in mathematics. Everything you see is the result of mathematical models that are constructed, analysed, and solved using functions.
If and only if a set of real numbers has a top and bottom bound, it is said to be bounded. This definition can be applied to any partially ordered set’s subsets. It’s worth noting that this broader concept of boundedness is unrelated to the concept of “size.”
If there is an element k in P such that k s for all s in S, the subset S of a partially ordered set P is called bounded above. The element k is referred to as a S upper bound. The terms bordered below & lower bound are used interchangeably.