Cf: Peirce’s 1870 “Logic of Relatives” • Comment 11.7
https://inquiryintoinquiry.com/2014/05/05/peirces-1870-logic-of-relatives-c…
Peirce’s 1870 “Logic of Relatives” • Comment 11.7
https://oeis.org/wiki/Peirce%27s_1870_Logic_Of_Relatives_%E2%80%A2_Part_2#C…
All,
We come now to the special cases of dyadic relations
known as functions. It will serve a dual purpose in
the present exposition to take the class of functions
as a source of object examples for clarifying the more
abstruse concepts of Relation Theory.
To begin, let us recall the definition of a
“local flag” L_{a @ j} of a k-adic relation L.
Display 1
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For a dyadic relation L ⊆ X × Y the notation for local flags
can be simplified in two ways.
First, the local flags L_{u @ 1} and L_{v @ 2} are often more
conveniently notated as L_{u @ X} and L_{v @ Y}, respectively.
Second, the notation may be streamlined even further by making
the following
definitions.
Display 2
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In light of these conventions, the local flags of a dyadic relation
L ⊆ X × Y may be comprehended under the following descriptions.
Display 3
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The following definitions are also useful.
Display 4
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A sufficient illustration is supplied by the earlier example E.
Figure 35. Dyadic Relation E
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Figure 36 shows the local flag E_{3 @ X} of E.
Figure 36. Local Flag E_{3 @ X}
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Figure 37 shows the local flag E_{2 @ Y} of E.
Figure 37. Local Flag E_{2 @ Y}
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Regards,
Jon