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On 09/02/2024 02:46 PM, Jim Burns wrote:On 9/1/2024 2:44 PM, Ross Finlayson wrote:
Then the point that induction lets out is>
at the Sorites or heap,
for that Burns' "not.first.false", means
"never failing induction first thus
being disqualified arbitrarily forever",
Not.first.false is about formulas which
are not necessarily about induction.
>
A first.false formula is false _and_
all (of these totally ordered formulas)
preceding formulas are true.
>
A not.first.false formula is not.that.
>
not.first.false Fₖ ⇔
¬(¬Fₖ ∧ ∀j<k:Fⱼ) ⇔
Fₖ ∨ ∃j<k:¬Fⱼ ⇔
∀j<k:Fⱼ ⇒ Fₖ
>
A finite formula.sequence S = {Fᵢ:i∈⟨1…n⟩} has
a possibly.empty sub.sequence {Fᵢ:i∈⟨1…n⟩∧¬Fᵢ}
of false formulas.
>
If {Fᵢ:i∈⟨1…n⟩∧¬Fᵢ} is not empty,
it holds a first false formula,
because {Fᵢ:i∈⟨1…n⟩} is finite.
>
If each Fₖ ∈ {Fᵢ:i∈⟨1…n⟩} is not.first.false,
{Fᵢ:i∈⟨1…n⟩∧¬Fᵢ} does not hold a first.false, and
{Fᵢ:i∈⟨1…n⟩∧¬Fᵢ} is empty, and
each formula in {Fᵢ:i∈⟨1…n⟩} is true.
>
And that is why I go on about not.first.false.
Then about not.first.falseWhat I find poetic about not.first.false and all that
thanks for writing that up a bit more,
then that also you can see what I make of it.
Not.ultimately.untrue, ..., has that"Not.ultimately.untrue" sounds to me vaguely like "ω-consistent".
F, bears the value for all F_alpha parameterized by ordinals
(which suffice, large enough, to totally order things),
of true, and that,
there are classes of formulas F,
for example self-referential or differential formulas,
defined for example according to
"when F_alpha is not also as for an ordinal less than omega",
at least making a trivial clear example of
a definition that is for classes of these sorts formulas
where "not.ultimately.untrue" is not held by all classes
for formulas "not.first.false".
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