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→Logical Graph Sandbox: dichotomy principle
==Logical Graph Sandbox==
==Logical Graph Sandbox==
More thoughts on Peirce's law …
===More thoughts on Peirce's law===
1-way version
1-way version
: <math>ab \lor a = a</math>
: <math>ab \lor a = a</math>
===The allegedly counterintuitive dichotomy law===
It is usually written in this form:
: <math>(p \Rightarrow q) \lor (q \Rightarrow p)</math>
Written as an order law, its sense is more sensible:
: <math>(p \le q) \lor (q \le p)</math>
Here it is in logical graphs:
<pre>
q o o p
| |
p o o q
| |
o o
\ /
o
|
@ = @
</pre>