Body na hranicích domén (trocha AJ v popisu)

Ahoj, omlouvám se, že je to v AJ, ale snad s tím nikdo nebude mít problém. Absolutně nechápu (vysvětlím níže):

The domain analysis process guides us in choosing efficient and effective test cases. First, a number of definitions:

An on point is a value that lies on a boundary.

An off point is a value that does not lie on a boundary.

An in point is a value that satisfies all the boundary conditions but does not lie on a boundary.

An out point is a value that does not satisfy any boundary condition.

Choosing on and off points is more complicated that it may appear.

When the boundary is closed (defined by an operator containing an equality, i.e., ≤, ≥ or =) so that points on the boundary are included in the domain, then an on point lies on the boundary and is included within the domain. An off point lies outside the domain.

When the boundary is open (defined by an inequality operator < or > so that points on the boundary are not included in the domain, then an on point lies on the boundary but is not included within the domain. An off point lies inside the domain.

<img src=http://flylib.com/books/2/156/1/html/2/images/fig137_01.jpg>

Figure 8-2: Examples of on, off, in, and out points for both closed and open boundaries.

On the left is an example of a closed boundary. The region defined consists of all the points greater than or equal to 10. The on point has the value 10. The off point is slightly off the boundary and outside the domain. The in point is within the domain. The out point is outside the domain.

On the right is an example of an open boundary. The region defined consists of all the points greater than (but not equal to) 10. Again, the on point has a value of 10. The off point is slightly off the boundary andi nside the domain. //PROČ? The in point is within the domain. The out point is outside the domain.

Proč při otevřeném kraji musí být OFF bod uvnitř domény? Nemá ležet na hranici, ale to by přece neležel ani tehdy, pokud by byl vně domény. U uzavřeného kraje je OFF bod mimo doménu, ale i tak nechápu, proč by nemohl být v ní, když by nebyl na okraji., Tohle je třetí kniha, která toto zmiňuje,ale nechápu proč.