An empty Kaucher interval
for
is defined as an interval where at least one of the bounds is undefined:
![- -
X= {[x,x]|x=∅ ∨ x= ∅}= ∅.](StabNumRef_PG149x.png)
Here,
, meaning the empty interval is not a real-valued interval. Consequently, no arithmetic operations can be
performed on an empty interval.
In computational implementations, the empty interval 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.