The following diagram shows that 40 \(\not \Rightarrow\) 391 is a code 6 non-implication, and the theory of transferability then shows that it is actually a code 4. It follows that the non-implication 155 \( \not \Rightarrow \) 391 is not just a code 6 non-implication, but is also a code 4 non-implication.
| 391 | This form is negation transferable | |||
| \(\Downarrow\) | ||||
| 399 | ||||
| \(\Downarrow\) | ||||
| 202 | \( \not \Rightarrow \) | 323 | ||
| \( \Downarrow \) | ||||
| This form is transferable | 40 | |||
| \( \Downarrow \) | ||||
| 43 | ||||
| \( \Downarrow \) | ||||
| 78 | ||||
| \( \Downarrow \) | ||||
| 155 |