Chapter 4 : Inner Order
Majority
Min
Inner Order
4A. Majority
Let
M(x,y,z) denote the form [[xy][yz][zx]].
In
Kleenean terms:
M(x,y,z) = (x
& y) V (y & z) V (z & x)
M(x,y,z) = (x
V y) & (y V z) & (z V x)
Exercise
for the student:
Derive
these theorems:
Majority: [[xy][yz][zx]] = [[x][y]]
[[y][z]] [[z][x]]
Symmetry: M(x,y,z) = M(z,y,x)
= M(x,z,y) =
other permutations
Coalition: M(x,
x, y) = x
Transmission: [ M(x,y,z) ]
= M([x],[y],[z])
Distribution: x
M(a,b,c) = M(xa, b, xc)
Redistribution: [[x][M(a,b,c)]] = M([[x][a]], b,
[[x][c]])
Collection:
M(x,y,z)) = [[x][y]] [ [xy] [z] ]
General
Distribution: M(x,y,M(a,b,c)) = M(M(x,y,a),b,M(x,y,c))
General
Associativity: M(x,a,M(y,a,z)) =
M(M(x,a,y), a, z)
Mediocrity: M(0,6,1) = 6
Therefore
these operators:
M(x,[[]],y) = [[x][y]]
M(x,[],y) = xy
M(x,6,y)
= [[x6][y6][xy]]
have
these properties: recall; commutativity; associativity; attractors ( [[]], []
and 6 respectively); and mutual
distribution.
4B. Min
Define the operator min
this way:
x min y = M(x,6,y)
x min y
F I
T
F F I I
F F I I
I I
I I
T I
I T
It has these laws:
Recall: x min x = x
Commutativity: x min y = y min x
Attractor: x min 6 = 6
Opposition: x min (~ x) = 6
Associativity: x min (y min z) = (x min y) min z
Transmission: not(x min y) = (not
x) min (not y)
Distribution: x min (y & z) = (x min y) & (x min z)
x
min (y V z) = (x min y) V (x min z)
x
& (y min z) = (x & y) min (x & z)
x
V (y min z) = (x V y) min (x V z)
4C. Inner order
Now let’s define “inner
order”:
x < y iff x min y =
x
t
<
i
<
f
Exercises for the student:
Prove these Theorems:
Theorem: min is the minimum operator for < ;
(X min Y) < X
; (X min Y) <
Y ;
and Z < (X min Y) , if Z<X and Z<Y
Theorem: < is transitive and
antisymmetric:
a < b
and b < c implies a
< c
a < b
and b <
a implies a
= b
Theorem: < is preserved by disjunction
and conjunction:
a <
b implies
a V c <
b V c
and a
& c < b &
c
Theorem: < is preserved by negation:
a <
b implies
~a < ~b .
Theorem: < is preserved by any Kleenean function:
a <
b implies
F(a) < F(b)
Theorem: For any Kleenean f;
f(x min
y) < f(x) min f(y)
Extend < to ordered form vectors:
x = (
x1, x2, x3, ... , xn )
x < y if and only if ( xi < yi ) for all i
Theorem: < has “limited chains”, with limit N.
That is,
if x n is an ordered chain of finite form vectors;
And x1
< x2 < x3
< ...
and if N
is the dimension of these vectors,
then for
all n > N, x n = x
N .
Proof:
Any given component of the x’s can move at most one step left before ending
up at I, or at most one step right before ending up at T or F; then that
component stops moving. For N components, this implies at most N steps in an
ordered chain before it stops moving.
Given
any Kleenean function f(x), define
a right
seed for f is any vector a such that a < f(a).
a fixedpoint
for f is any vector a such that
a = f(a).
A
fixedpoint is also a right seed.
Right seeds
generate fixedpoints, thus:
If a
is a right seed for f, then a < f(a).
Since f is Kleenean, it preserves inner order; so f (a)
< f2(a); and f
2(a) < f 3(a);
and so on:
a < f(a) < f
2(a) < f 3(a) < f
4(a) < ...
This ascending
sequence must reach its upper bound within n steps, if n is the number of
components of f. Therefore f n(a) is a fixedpoint
for f:
f(f n(a)) = f
n(a)
Right
seeds grow rightwards towards fixedpoints.
If b
is a fixedpoint right of a, then it’s also right of fn(b)
for all n, including the fixedpoint. Therefore fn(a)
is the leftmost fixedpoint right of a.
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