3.5.1 Empty Triplex

An empty triplex value for is defined as a degenerate case where all components are undefined or null:

This represents the absence of a valid triplex value, analogous to the empty set in interval arithmetic.

In computational implementations, the empty triplex is typically represented using qNaN (Quiet-Not-a-Number) values. Any arithmetic operation involving a qNaN will propagate the qNaN, ensuring that invalid or undefined operations do not yield misleading results.