Circular reference

Indeed, it can be argued that self-reference is a necessary consequence of Aristotle's Law of non-contradiction, a fundamental philosophical axiom.

For example, the two functions, posn and plus1 in the following Python program comprise a circular reference:[further explanation needed] Circular references like the above example may return valid results if they have a terminating condition.

In ISO Standard, SQL circular integrity constraints are implicitly supported within a single table.

In that case the constraint is checked at the end of the transaction not at the time the DML statement is executed.

[4] A distinction should be made with processes containing a circular reference between those that are incomputable and those that are an iterative calculation with a final output.