Browse Definitions :
Definition

# null set

In mathematical sets, the null set, also called the empty set, is the set that does not contain anything. It is symbolized or { }. There is only one null set. This is because there is logically only one way that a set can contain nothing.

The null set makes it possible to explicitly define the results of operations on certain sets that would otherwise not be explicitly definable. The intersection of two disjoint sets (two sets that contain no elements in common) is the null set. For example:

{1, 3, 5, 7, 9, ...} {2, 4, 6, 8, 10, ...} =

The null set provides a foundation for building a formal theory of numbers. In axiomatic mathematics, zero is defined as the cardinality of (that is, the number of elements in) the null set. From this starting point, mathematicians can build the set of natural numbers, and from there, the sets of integers and rational numbers.

This was last updated in September 2005
• ISO 31000 Risk Management

The ISO 31000 Risk Management framework is an international standard that provides businesses with guidelines and principles for ...

• pure risk

Pure risk refers to risks that are beyond human control and result in a loss or no loss with no possibility of financial gain.

• risk reporting

Risk reporting is a method of identifying risks tied to or potentially impacting an organization's business processes.

• What is cyber hygiene and why is it important?

Cyber hygiene, or cybersecurity hygiene, is a set of practices individuals and organizations perform regularly to maintain the ...

• Pretty Good Privacy (PGP)

Pretty Good Privacy or PGP was a popular program used to encrypt and decrypt email over the internet, as well as authenticate ...

• email security

Email security is the process of ensuring the availability, integrity and authenticity of email communications by protecting ...

• What is risk mitigation?

Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a business.

• fault-tolerant

Fault-tolerant technology is a capability of a computer system, electronic system or network to deliver uninterrupted service, ...

• synchronous replication

Synchronous replication is the process of copying data over a storage area network, local area network or wide area network so ...

• information lifecycle management (ILM)

Information lifecycle management (ILM) is a comprehensive approach to managing an organization's data and associated metadata, ...

• WORM (write once, read many)

In computer media, write once, read many, or WORM, is a data storage technology that allows data to be written to a storage ...

• direct access

In computer storage, direct access is the process of reading and writing data on a storage device by going directly to where the ...

Close