Cf: Peirce’s 1870 “Logic of Relatives” • Comment 12.5
https://inquiryintoinquiry.com/2014/06/15/peirces-1870-logic-of-relatives-c…
Peirce’s 1870 “Logic of Relatives” • Comment 12.5
https://oeis.org/wiki/Peirce%27s_1870_Logic_Of_Relatives_%E2%80%A2_Part_2#C…
All,
The equation (s^ℓ)^w = s^(ℓw) can be verified by
establishing the corresponding equation in matrices.
• (S^L)^W = S^(LW)
If A and B are two 1-dimensional matrices over the
same index set X then A = B if and only if A_x = B_x
for every x in X. Thus, a routine way to check the
validity of (S^L)^W = S^(LW) is to check whether
the following equation holds for arbitrary x in X.
• ((S^L)^W)_x = (S^(LW))_x
Taking both ends toward the middle, we proceed as follows.
Matrix Equation ((S^L)^W)_x = (S^(LW))_x
https://inquiryintoinquiry.files.wordpress.com/2022/04/lor-1870-s5el5ew_x-s…
The products commute, so the equation holds. In essence, the matrix
identity turns on the fact that the law of exponents (a^b)^c = a^(bc)
in ordinary arithmetic holds when the values a, b, c are restricted to
the boolean domain B = {0, 1}. Interpreted as a logical statement, the
law of exponents (a^b)^c = a^(bc) amounts to a theorem of propositional
calculus otherwise expressed in the following ways.
• ((a ⇐ b) ⇐ c) = (a ⇐ b ∧ c)
• (c ⇒ (b ⇒ a)) = (c ∧ b ⇒ a)
Regards,
Jon