Mathematical Duality in Logical Graphs • Discussion 2
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https://inquiryintoinquiry.com/2024/05/04/mathematical-duality-in-logical-graphs-discussion-2/
Re: Interpretive Duality in Logical Graphs • 1
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https://inquiryintoinquiry.com/2024/04/22/interpretive-duality-in-logical-graphs-1/
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https://groups.io/g/lawsofform/message/139
<QUOTE LA:>
Definition 1. A group (G, ∗) is a set G together
with a binary operation ∗ : G × G → G satisfying
the following three conditions.
1. Associativity. For any x, y, z ∈ G,
we have (x ∗ y) ∗ z = x ∗ (y ∗ z).
2. Identity. There is an identity element e ∈ G
such that ∀ g ∈ G, we have e ∗ g = g ∗ e = g.
3. Inverses. Each element has an inverse, that is,
for each g ∈ G, there is some h ∈ G such that
g ∗ h = h ∗ g = e.
</QUOTE>
Dear Lyle,
Thanks for supplying that definition of a mathematical group.
It will afford us a wealth of useful concepts and notations
as we proceed. As you know, the above three axioms define
what is properly called an “abstract group”. Over the
course of group theory's history that definition was
gradually abstracted from the more concrete examples
of permutation groups and transformation groups initially
arising in the theory of equations and their solvability.
As it happens, the application of group theory I'll be developing
over the next several posts will be using the more concrete type
of structure, where a “transformation group” G is said to “act on”
a set X by permuting its elements among themselves. In the work
we do here, each group G we contemplate will be acting on a set X
which may be taken as either one of two things, either a canonical
set of expressions in a formal language or the mathematical objects
denoted by those expressions.
What you say about deriving arithmetic, algebra, group theory,
and all the rest from the calculus of indications may well be
true, but it remains to be shown if so, and that's aways down
the road from here.
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