Definitions for

**"Invariant"**An invariable quantity; specifically, a function of the coefficients of one or more forms, which remains unaltered, when these undergo suitable linear transformations.

Some aspect of the proximal stimulus pattern that remains unchanged despite various transformations of the stimulus.

A quantity that does not change when transformed.

(n.) a variable, especially in a DO-loop, that appears only on the right side of an equals sign. The variable is read only, it is never assigned a new value.

An invariant is a type of assertion that describes a relationship between variables that holds as the values of those variables change. A special type of invariant is the loop invariant.

An Assertion about some design element that must be true at all times, except during specifically transient situations such as the middle of the execution of a method, or the middle of an uncommitted database transaction.

a polynomial function of the probability distribution defined by a stochastic model for the observed nucleotide sequence

a polynomial in these probabilities that, for a given phylogeny, is zero for all choices of the substitution mechanism parameters

There are two meanings. One is that associated with DbC whereby the invariant describes some condition that must prevail throughout execution of a class or subsystem responsibility. The other meaning refers to abstracting aspects of the problem space that do not change across a large class of problems. Linear programming, Keplar's Laws, and double entry bookkeeping all represent invariants that can be abstracted the same way across a number of particular problem contexts without change. (See the category on invariants.)

An invariant is a condition that does not change, or should not, if the system is working correctly.

a constraint on the

a constraint that states a condition that must always be met by all instances of the class, type, or interface

a predicate on the state of the object

an output cell of type Boolean