[Inquiry] Re: Cactus Rules

[Jon Awbrey]

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CR.  Note 7

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Had I been thinking ahead, I might have mentioned this first,
but now that aspects of algebra and geometry have intruded on
our logical paradise, in the guise of the dual space X*, let's
give belated notice to one family of propositions that have been
basic to our enterprise all along, whether we noticed them or not.

In a k-dimensional universe of discourse X% = [x_1, ..., x_k] the
position space X = <|x_1, ..., x_k|> is isomorphic to B^k and the
proposition space X^ = (X -> B) = {f : X -> B} bears the abstract
type B^k -> B.  In algebra and geometry, as a rule, one tends to
take position spaces and function spaces together in pairs, and
so we assign the universe X% a "stereotype" of <B^k, B^k -> B>,
or B^k +-> B, for short.  I like to think of these spaces as
the "paint layer" X and "draw layer" X^ of the universe X%.

What I need to make a point of at this point is that the k-set
of logical features !X! = {x_1, ..., x_k} that we invoke as the
basis of the universe of discourse also constitutes an important
family of propositions x_j : B^k -> B, for j = 1 to k.  These are
called by any one of several different names:  "basic propositions",
"coordinate projections", or "simple propositions".

Table 0 accords this family of simple propositions their
formal recognition, for the present case of 3 dimensions.

Table 0.  Simple Propositions
o---------o------------o-----------------o-------------------o
| L_1 ` ` | L_2 ` ` ` `| L_3 ` ` ` ` ` ` | L_4 ` ` ` ` ` ` ` |
| ` ` ` ` | ` ` ` ` ` `| ` ` ` ` ` ` ` ` | ` ` ` ` ` ` ` ` ` |
| Decimal | Binary` ` `| Vector` ` ` ` ` | Cactus` ` ` ` ` ` |
o---------o------------o-----------------o-------------------o
| ` ` ` ` | ` ` ` ` `p : 1 1 1 1 0 0 0 0 | ` ` ` ` ` ` ` ` ` |
| ` ` ` ` | ` ` ` ` `q : 1 1 0 0 1 1 0 0 | ` ` ` ` ` ` ` ` ` |
| ` ` ` ` | ` ` ` ` `r : 1 0 1 0 1 0 1 0 | ` ` ` ` ` ` ` ` ` |
o---------o------------o-----------------o-------------------o
| ` ` ` ` | ` ` ` ` ` `| ` ` ` ` ` ` ` ` | ` ` ` ` ` ` ` ` ` |
| q_240 ` | q_11110000 | 1 1 1 1 0 0 0 0 | ` `p` ` ` ` ` ` ` |
| ` ` ` ` | ` ` ` ` ` `| ` ` ` ` ` ` ` ` | ` ` ` ` ` ` ` ` ` |
| q_204 ` | q_11001100 | 1 1 0 0 1 1 0 0 | ` ` ` ` q ` ` ` ` |
| ` ` ` ` | ` ` ` ` ` `| ` ` ` ` ` ` ` ` | ` ` ` ` ` ` ` ` ` |
| q_170 ` | q_10101010 | 1 0 1 0 1 0 1 0 | ` ` ` ` ` ` `r` ` |
| ` ` ` ` | ` ` ` ` ` `| ` ` ` ` ` ` ` ` | ` ` ` ` ` ` ` ` ` |
o---------o------------o-----------------o-------------------o

Of course, we've already seen this 3-set of basic propositions
numbered among the (2^3)-set of linear propositions in Table 2.

Additional discussion of these underpinnings can be found here:

| Jon Awbrey, "Differential Logic and Dynamic Systems"
| http://stderr.org/pipermail/inquiry/2003-May/thread.html#478
| http://stderr.org/pipermail/inquiry/2003-June/thread.html#553

Especially:

DLOG D2.  http://stderr.org/pipermail/inquiry/2003-May/000480.html
DLOG D5.  http://stderr.org/pipermail/inquiry/2003-May/000483.html

With that out of the way, I'll try to
get back to the main event next time.

Jon Awbrey

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inquiry e-lab: http://stderr.org/pipermail/inquiry/
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