Empty set
mathematical set containing no elements
Wikipedia
en.wikipedia.org › wiki › Null_(mathematics)
Null (mathematics) - Wikipedia
May 4, 2025 - In mathematics, the word null (from German: null meaning "zero", which is from Latin: nullus meaning "none") is often associated with the concept of zero, or with the concept of nothing. It is used in varying contexts from "having zero members in a set" (e.g., null set) to "having a value of ...
Wikipedia
en.wikipedia.org › wiki › Null_sign
Null sign - Wikipedia
June 13, 2025 - The null sign (∅) is a symbol often used in mathematics for denoting the empty set. The same letter in linguistics represents zero, the lack of an element.
Videos
06:22
Null Set or Empty Set : Sets | Mathematics | AP&TS - YouTube
00:26
Null set Meaning - YouTube
02:08
What is a Null Set | Is Null Set a Subset of Every Set? | Don't ...
02:08
The Empty Set or the Null Set , Intermediate Algebra , Lesson 27 ...
Introduction to the null space of a matrix (video)
Wikipedia
en.wikipedia.org › wiki › Null
Null - Wikipedia
1 month ago - Null (mathematics), a zero value in several branches of mathematics
Top answer 1 of 4
4
The distinction between the empty set 
and the number 
is similar to that between NULL and ZERO. For example, the set of real solutions (or informally "the solution") to 
is 
, but the solution to 
is 
.
2 of 4
4
In my mind there is no need for a concept like NULL in mathematics if you think of NULL as in NULL-pointers.
NULL in this sense is a technical necessity because you cannot un-define a variable: Once a variable has been assigned a value, a certain bit of memory is reserved for this variable and this memory is marked as re-usable only if the variable goes out of scope (simplified speaking).
You cannot say "The variable with this name doesn't exist anymore." without letting it go out of scope, because that would make language interpretation much more complicated without many benefits. Therefore, to indicate that the value of the variable has no meaning, one uses NULL.
What NULL stands for in the end depends upon the programming language: In some it is a special keyword, but in some it is also just a different name for the integer 
.
You can assign an arbitrary value to NULL in mathematics as mentioned in the other replies (
, 
, etc.) but as mathematics has nothing to do with memory allocation there is really no need for such a thing as NULL.
ScienceDirect
sciencedirect.com › topics › mathematics › null
Null - an overview | ScienceDirect Topics
NULL refers to a special marker used in computing and mathematics that indicates the absence of a value, where a NULL argument in functions results in a NULL output of the appropriate data type.
Cuemath
cuemath.com › algebra › empty-set
Empty Set - Definitions, Properties, Examples | Null Set
An empty set is denoted using the symbol '∅'. It is read as 'phi'. Example: Set X = {}. It is also called a void set or null set. Empty sets are considered to be unique when compared to other sets.
Quora
quora.com › What-exactly-is-NULL
What exactly is NULL? - Quora
Answer (1 of 25): It means nothing. Most literally. It means that it has no meaning. It can best be understood when dealing with dates and numbers. Alpha-numeric NULL is awkward and not really accurate, as it differentiates between a blank string and the lack of value represented by NULL. With ...
Wolfram Language
reference.wolfram.com › language › ref › Null.html.en
Null
Null represents the absence of content or elements in such constructs as InputField or Grid. When a sequence of commands ends with a semicolon, no output is shown: The full form of the output is Null: If you forget a semicolon in a program you ...
Encyclopedia Britannica
britannica.com › science › null-set
Null set | mathematics | Britannica
The empty (or void, or null) set, symbolized by {} or Ø, contains no elements at all.
Wolfram Language
reference.wolfram.com › language › ref › Null.html
Null - Wolfram Language Documentation
Null represents the absence of content or elements in such constructs as InputField or Grid. When a sequence of commands ends with a semicolon, no output is shown: The full form of the output is Null: If you forget a semicolon in a program you ...
CK-12 Foundation
ck12.org › all subjects › cbse math › sets and its types › what is a null set in maths?
What is a null set in maths? - Symbol & Definition | CK-12 Foundation
September 11, 2025 - In mathematics, a null set, also known as an empty set, is a set that contains no elements. It is denoted by the symbol @$\begin{align*}\emptyset\end{align*}@$ or @$\begin{align*}\{\}\end{align*}@$. For example, the set of all integers that are both even and odd is a null set, because no integer ...
Wikipedia
en.wikipedia.org › wiki › Empty_set
Empty set - Wikipedia
3 days ago - In mathematics, the empty set or void set is the unique set having no elements; its size or cardinality (count of elements in a set) is zero. Some axiomatic set theories ensure that the empty set exists by including an axiom of empty set, while ...
Merriam-Webster
merriam-webster.com › dictionary › null
NULL Definition & Meaning - Merriam-Webster
In mathematics, it is sometimes used to mean "containing nothing"; for example, the set of all whole numbers that are divisible by zero is the "null set" (that is, there are no numbers that fit that description).
Abbreviationstandfor
abbreviationstandfor.com › 2015 › 04 › what-does-null-stand-for.html
Abbreviations, Full form, Means and Definition?: What does NULL stand for?
It's distinct from a set that contains nothing, as the empty set itself is a mathematical concept. In philosophy, "NULL" can be associated with existential concepts, representing a void or absence of being. Existentialist thinkers often explore the idea of nothingness, which relates to the ...
Cuemath
cuemath.com › calculus › zero-vector
Zero Vector (Null Vector) - Definition, Examples
Now, a vector that has zero length and an undefined direction is called a zero vector or null vector. It has all components equal to 0. In this article, we will study the concept of zero vector, its definition, and symbol and solve some examples ...
Study.com
study.com › courses › standardized tests courses › gmat study guide and test prep
Null Set Definition, Properties & Examples - Lesson | Study.com
July 7, 2016 - The null set is useful in mathematics and especially discrete mathematics. For instance, the natural numbers are formed by utilizing the empty set. Without it, the very foundation of number theory would not exist. The null set is also used to derive and prove multiple mathematical rules and ...
Wolfram MathWorld
mathworld.wolfram.com › NullVector.html
Null Vector -- from Wolfram MathWorld
September 5, 2019 - There are several meanings of "null vector" in mathematics. 1. The most common meaning of null vector is the n-dimensional vector 0 of length 0. i.e., the vector with n components, each of which is 0 (Jeffreys and Jeffreys 1988, p. 64). 2. When applied to a matrix A, a null vector is a nonzero vector x with the property that Ax=0. 3. When applied to a vector space X with an associated quadratic form q, a null vector is a nonzero element x of X for which q(x)=0. 4. When applied...
TechTarget
techtarget.com › whatis › definition › data-set
What is a null set in mathematics?
The following four script samples show the record in each format: ... 172653,375,Nitrogen dioxide (NO2),Mean,ppb,UHF34,203,Bedford Stuyvesant – Crown Heights,Annual Average 2011,12/01/2010,25.3 ... [ "row-frzi_7bar_4cbg", "00000000-0000-0000-AF08-C339B5581012", 0, 1698955938, null, 1698955938, null, "{ }", "172653", "375", "Nitrogen dioxide (NO2)", "Mean", "ppb", "UHF34", "203", "Bedford Stuyvesant – Crown Heights", "Annual Average 2011", "2010-12-01T00:00:00", "25.30", null ]
Wikiwand
wikiwand.com › en › Null_(mathematics)
Null (mathematics) - Wikiwand
In mathematics, the word null is often associated with the concept of zero, or with the concept of nothing. It is used in varying contexts from "having zero mem...