Cf: Peirce’s 1870 “Logic of Relatives” • Comment 12.1
https://inquiryintoinquiry.com/2014/06/10/peirces-1870-logic-of-relatives-c…
Peirce’s 1870 “Logic of Relatives” • Comment 12.1
https://oeis.org/wiki/Peirce%27s_1870_Logic_Of_Relatives_%E2%80%A2_Part_2#C…
All,
To get a better sense of why Peirce’s formulas in Selection 12
mean what they do, and to prepare the ground for understanding
more complex relational expressions, it will help to assemble
the following materials and definitions.
• X is a set singled out in a particular discussion
as the “universe of discourse”.
• W ⊆ X is the monadic relation, or set, whose elements
fall under the absolute term w = woman. The elements
of W are referred to as the “denotation” or “extension”
of the term w.
• L ⊆ X × X is the dyadic relation associated with the
relative term ℓ = lover of___.
• S ⊆ X × X is the dyadic relation associated with the
relative term s = servant of___.
• \mathsf{W} = Mat(W) = Mat(w) is the 1-dimensional matrix
representation of the set W and the term w.
• \mathsf{L} = Mat(L) = Mat(ℓ) is the 2-dimensional matrix
representation of the relation L and the relative term ℓ.
• \mathsf{S} = Mat(S) = Mat(s) is the 2-dimensional matrix
representation of the relation S and the relative term s.
The “local flags” of the relation L are defined as follows.
• u ∗ L
= L_u@1
= {(u, x) ∈ L}
= ordered pairs in L with u in the 1st place.
• L ∗ v
= L_v@2
= {(x, v) ∈ L}
= ordered pairs in L with v in the 2nd place.
The “applications” of the relation L are defined as follows.
• u ∙ L
= proj₂(u ∗ L)
= {x ∈ X : (u, x) ∈ L}
= loved by u.
• L ∙ v
= proj₁(L ∗ v)
= {x ∈ X : (x, v) ∈ L}
= lover of v.
Regards,
Jon