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connection with
= a
R
= a W |∀ b b S implies (a,b) R 1
λ(S)
W
|∀
b
S.(b,a)
= a
b (a,b) /
S
R 1
|∀
implies b/
= a
b (a,b)
K
R 1
|∀
does not imply b
φ
= a
b (a,b)
M |= b φ
R 1
|∀
does not imply
={
a
| M |= a R 1
¬ c φ
}= R 1
¬ c φ
K .
Thus, the modal additive algebraic negation λ is represented by a composition
R 1
¬ c of the universal modal operator
R 1
and classic (standard) logical nega-
tion
¬ c . Analogously,
= a
R
ρ(S)
W
|∀
b
S.(a,b)
= a
b b
R
W
|∀
S implies (a,b)
= a
b (a,b) /
S
|∀
R implies b/
= a |∀ b (a,b) R
does not imply b φ K
= a
b (a,b)
M |= b φ
|∀
R does not imply
={
a
| M |= a R ¬ c φ
}
= R ¬ c φ
K .
Thus, the modal multiplicative algebraic negation ρ is represented by a composition
R ¬ c of the universal modal operator
R
and classic (standard) logical negation
¬ c .
Consequently, the closure operator Γ = ρλ is represented by the composition
(
R ¬ c )(
R 1
¬ c ).
That is, from the fact that
¬ c R 1
¬ c is equal to the existential modal operator
R 1
,
R R 1
we obtain that Γ is represented by modal composition
.
In fact, it is easy to verify that the Kripke semantics of the closure operator Γ
corresponds to
b
b ,
M |= a R R 1
M |= c φ implies c
φ
iff
c(
b) implies a
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