Definition - What does Invariant mean?
An invariant is a value or condition that is expected to be consistent during the execution of a process. Invariants are useful in testing the results of algorithms and the integrity of computer programs. Their predictability can simplify the process of assessing the validity of logical assertions, and invariants can be seen as points of reference within surrounding context.
Techopedia explains Invariant
The earliest published observations of invariant phenomena are said to exist in Carl Friedrich Gauss’s widely influential late-eighteenth century text on number theory, “Disquititiones Arithmeticae.” However, the innovation of a fully formed invariant theory is often accredited to George Boole, who wrote about it for the Cambridge Mathematical Journal in the early 1840s. Other prominent researchers who have expanded on the subject include Otto Hesse and Arthur Cayley (both of whom are European mathematicians from the nineteenth century).