Differential Logic • 16
•
https://inquiryintoinquiry.com/2024/11/19/differential-logic-16-a/
Propositions and Tacit Extensions —
Now that we've introduced the field picture as an aid to visualizing
propositions and their analytic series, a pleasing way to picture
the relationship of a proposition f : X → B to its enlargement or
shift map Ef : EX → B and its difference map Df : EX → B can now
be drawn.
To illustrate the possibilities, let's return to the differential
analysis of the conjunctive proposition f(p, q) = pq and give its
development a slightly different twist at the appropriate point.
The proposition pq : X → B is shown again in the venn diagram below.
In the field picture it may be seen as a scalar field — analogous to
a “potential hill” in physics but in logic amounting to a “potential
plateau” — where the shaded region indicates an elevation of 1 and
the unshaded region indicates an elevation of 0.
Proposition pq : X → B
•
https://inquiryintoinquiry.files.wordpress.com/2024/11/field-picture-pq-con…
Given a proposition f : X → B, the “tacit extension” of f to EX is
denoted εf : EX → B and defined by the equation εf = f, so it's
really just the same proposition residing in a bigger universe.
Tacit extensions formalize the intuitive idea that a function
on a given set of variables can be extended to a function on
a superset of those variables in such a way that the new
function obeys the same constraints on the old variables,
with a “don't care” condition on the new variables.
The tacit extension of the scalar field pq : X → B to the
differential field ε(pq) : EX → B is shown in the following
venn diagram.
Tacit Extension ε(pq) : EX → B
•
https://inquiryintoinquiry.files.wordpress.com/2024/11/field-picture-pq-tac…
ε(pq)
= p ∙ q ∙ (dp)(dq)
+ p ∙ q ∙ (dp) dq
+ p ∙ q ∙ dp (dq)
+ p ∙ q ∙ dp dq
Resources —
Logic Syllabus
•
https://inquiryintoinquiry.com/logic-syllabus/
Survey of Differential Logic
•
https://inquiryintoinquiry.com/2024/02/25/survey-of-differential-logic-7/
Regards,
Jon
cc:
https://www.academia.edu/community/V00dPp
cc:
https://www.researchgate.net/post/Differential_Logic_The_Logic_of_Change_an…