2.5 First order proof system

Some axioms for the first order case are shown in Table 8.
Let V denote a state variable.
We denote by f [e ∕ V ] that in formula f expression e is substituted for variable V .

Table 8: Some First Order Axioms and Rules for finite ITL.
ForallSub
⊢ ∀V f ⊃ f [e ∕ V ],
where the expression e has the same data
and temporal type as the variable V and
is free for V in f.
ForallImplies
⊢ ∀V (f1 ⊃ f2) ⊃ (f1 ⊃ ∀V f2),
where V doesn’t occur freely in f1.
SubstAxiom
⊢ (V 1 = V 2) ⊃ f ≡ f [V 2 ∕ V 1].
ExistsChopRight
⊢ ∃V (f1 ; f2) ⊃ (∃V f1) ; f2,
where V doesn’t occur freely in f2.
ExistsChopLeft
⊢ ∃V (f1 ; f2) ⊃ f1 ; (∃V f2),
where V doesn’t occur freely in f1.
ForallGen
⊢ f ⇒ ⊢ ∀V f,
for any variable V .

2025-12-19
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