Chapter 3 : Kleenean Logic
Isomorphic to Kleenean logic
Differentials
Bochvarian operators
3A. Isomorphic to Kleenean logic
Consider these truth tables for
Kleenean logic:
xVy x F I T
y
F F I T
I I
I T
T T
T T
~x T
I F
x&y x F I T
y
F F F F
I F
I I
T F
I T
These tables are isomorphic to bracket forms twice, via S2.
In one matching, [xy] corresponds to (x
nor y); in the other, [xy] corresponds
to (x nand y); the “nor-gate” and
“nand-gate” interpretations.
These laws apply:
Swap: x V y = y V x
; x & y = y & x
Recall: x
V x = x & x
= x
Identity: x V
F =
x & T = x
Attractor: x V T = T
; x & F = F
3B. Differentials
Define the “differentials” this way:
The “lower differential”:
dx = x & ~x
The “upper differential”:
Dx = x V ~x
These are, respectively, in bracket
forms
[x[x]] ; x[x]
- in the nor-gate interpretation;
reverse order for nand-gate.
They have these tables:
F I T
dx F
I F
Dx T
I T
These laws apply:
Domination: (x
& dx) = (Dx & dx) =
dx ;
(x V Dx) =
(dx V Dx) = Dx ;
(dx V x) =
(Dx & x) = x
Negation: ~ dx = Dx
= D(~x) ;
~ Dx =
dx = d(~x)
Leibnitz Laws: d(x&y) = (x&dy)V(y&dx)
d(xVy) =
(~x&dy)V(~y&dx)
D(x&y) =
(~xVDy)&(~yVdx)
D(xVy) =
(xVDy)&(yVDx)
3C. Bochvarian operators
Here are the “Bochvarian” operators, defined in Kleenean logic:
x &B y = (x&y)
V dx V dy = (x&y) V (x&~x) V (y&~y)
x VB y = (xVy)
& Dx & Dy = (xVy) & (xV~x) & (yV~y)
These are, respectively, in bracket
forms
[[x][y]] [x[x]] [y[y]]
[ [xy] [x[x]] [y[y]] ]
- in the nor-gate
interpretation; reverse order for nand-gate.
They have these tables:
xVBy
x F I T
y
F F I T
y
F F I T
I I
I I
T T
I T
x&By x F I T
y
F F I F
I I
I I
T F
I T
These laws apply:
Swap: x VB y
= y VB x ; x
&B y = y &B x
Recall: x
VB x = x &B x = x
Identity: x
VB F = x &B T = x
Attractor: x VB I
= x &B I = I
Differentials: x VB T
= Dx ; x &B
F =
dx
In Bochvarian logic, I is an infinite
value; it dominates any expression it’s in. In Kleenean logic, I is an intermediate value; it can be dominated.
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