The following diagram shows that 31 \(\not \Rightarrow\) 290 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 420 \( \not \Rightarrow \) 290 is not just a code 6 non-implication, but is also a code 4 non-implication.
| 23 | \( \not \Rightarrow \) | 290 | This form is negation transferable | |
| \( \Downarrow \) | ||||
| 27 | ||||
| \( \Downarrow \) | ||||
| This form is transferable | 31 | |||
| \( \Downarrow \) | ||||
| 419 | ||||
| \( \Downarrow \) | ||||
| 420 |