The following diagram shows that 305 \(\not \Rightarrow\) 409 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 306 \( \not \Rightarrow \) 409 is not just a code 6 non-implication, but is also a code 4 non-implication.

409 This form is negation transferable
\(\Downarrow\)
62
\(\Downarrow\)
61
\(\Downarrow\)
45-n
\(\Downarrow\)
33-n
\(\Downarrow\)
67 \( \not \Rightarrow \) 47-n
\( \Downarrow \)
89
\( \Downarrow \)
90
\( \Downarrow \)
91
\( \Downarrow \)
This form is transferable 305
\( \Downarrow \)
306

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