Theorem, |
|
Dem.: Prop. Lemma, result.
Hence, by Perm., , i.e.
|
()
|
Syllogism, |
|
Dem.: In this Dem., Permutation is used to correct the twisting action of , much as handwriting has first to be inverted, if it is to be seen right in a mirror.
By Perm., and Perm.,
|
(a)
|
By Perm., , and Perm.,
|
(b)
|
By , result.
Association, |
|
The structure of the proof is this:
gives |
.
|
We now need only the Lemma for our result to follow by Syll. twice.
Lemma, |
|
The proof of this lemma—call it L—is as follows: We prove (a) , (b) . From this, by Syll. and Tautol., the result follows.
Dem.: (a) By ,
|
|
(1)
|