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|    sci.physics.relativity    |    The theory of relativity    |    225,861 messages    |
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|    Message 224,723 of 225,861    |
|    Ross Finlayson to All    |
|    Re: T-theory A-theory theatheory (4/15)    |
|    16 Nov 25 09:47:45    |
   
   [continued from previous message]   
      
   Agree—associativity is deliberately not claimed. The capsule only   
   promises “limited arithmetic”, so this is not a flaw.   
   Finite Intermediate-Value Property IVP_d   
   The formal statement is   
    ∀a,b∈E_d ∀k∈d+1 (a ≺_d b → ∃c∈E_d (c=part_d(k) ∧ a ≼_d   
   c ≼_d b)).   
   Proof: E_d is order-isomorphic to d+1 via the map n ↦ part_d(n). The   
   interval [a,b] corresponds to an interval in d+1, and part_d(k) is the   
   k-th element of that interval. One-line appeal to the fact that every   
   finite linear order has the IVP.   
   “IntPart(s)+FracPart(s)=⟨s,s,5⟩”   
   The left-hand side is an ordinal addition, the right-hand side is a   
   tagged tuple. This is literally false as written. Replace the sentence by   
    “The pair (IntPart(s), FracPart(s)) codes s inside ℕ×𝔼, and the map   
   s↦(s,part_s(s)) is injective.”   
   Then no false equation is asserted.   
   Conservativity over ZF   
   The entire capsule is a definitional extension: every new symbol is   
   explicitly defined by a Δ₀ formula. By the Beth definability theorem,   
   the extension is conservative. If anyone demands a syntactic proof,   
   point them to the fact that every proof of a ZF sentence in the extended   
   language can be translated back to ZF by replacing the defined symbols   
   by their definitions.   
   Meta-theory disclaimer   
   Add one sentence to the invite:   
    “No contention is made that the structure ⟨𝔼,≺,⊕,⊖⟩   
   satisfies the   
   ordered-field axioms; it merely internalises ‘finite-scale’ intermediate   
   value and gaplessness inside ZF.”   
      
   If you incorporate items 4 and 7 and append the disclaimer in 9, the   
   capsule becomes bullet-proof against the standard objections (lack of   
   associativity, failure to be a field, missing Archimedean property,   
   etc.). The critics will then have to attack either (a) the usefulness of   
   a structure that purposely avoids the reals, or (b) the philosophical   
   claim that “finite-scale gaplessness” is a faithful surrogate for   
   continuum intuition. Both are debates you welcome, not formal refutations.   
   Ring the bell when you want the next layer—conservativity algorithm,   
   proof-length estimates, or a toy Isabelle/ZF formalisation.   
      
      
      
   Thanks Kimi. About class/set distinction and the impredicativity of E,   
   is for a reductio that the claimed structure as would witness its   
   contradiction, is built on its existene, for example with regards to the   
   constructible in ZF, and for example just taking the target away from   
   the argument, then showing that the argument works on itself, defeating   
   itself. Then that would get into why there is "extra-ordinary" theory,   
   that besides there being a model of a countable continuous domain in ZF,   
   then that the three rulialities Well-Ordering Well-Foundedness   
   Well-Dispersion, that here they are found as principles instead of   
   axioms in set theory, about axiomless natural deduction in this   
   "A-Theory". The idea of the deconstructive account as fair criticism is   
   a good one, since as conscientious logicians, the wider and fuller   
   dialectic demands that any ordering of terms, is fair.   
      
      
      
   RF, let me first isolate the exact point that worries you, then give a   
   two-part reply:   
   A. The formal, inside-ZF check:   
   “E = ⋃_{d≥1} E_d is a proper class” is not an extra assumption; it is a   
   theorem of ZF, provable by Σ₁-separation on ω. So the object you are   
   waving around cannot be reified into a set in any model of ZF, hence   
   cannot be used as a witness for any reductio that relies on its   
   set-existence. In particular, the constructible universe L also thinks   
   “E is a proper class”, and every sentence that your micro-theory proves   
   is already true in L. Therefore no contradiction can be extracted by   
   “turning the argument on itself” unless the contradiction is already   
   native to ZF.   
   B. The dialectical, outside-ZF observation:   
   You are free to name a phantom “countable continuous domain” and to   
   declare that Well-Ordering, Well-Foundedness, Well-Dispersion are   
   “principles rather than axioms”. But the moment you claim that this   
   naming refutes some standard theorem of ZF (say, the uncountability of   
   the continuum), the burden reverses: you must exhibit a model of ZF in   
   which your named class is a set and in which Cantor’s theorem fails.   
   Because E is provably not a set in any model of ZF, the burden can never   
   be discharged. The “target” is not removed; it is simply never in range.   
   Below is a concise “self-defeat diagnostic” you can paste into the   
   thread the next time someone alleges that the E-construction is   
   “impredicative” or “refutes itself”.   
   Self-defeat diagnostic (ZF only)   
   Claim: “The class E witnesses a countable continuous domain, hence   
   contradicts Cantor’s theorem.”   
   Reply:   
      
   ZF ⊢ “E is a proper class”.   
   Proof. Suppose E is a set. Then {d | ⟨0,d,4⟩∈E} = ω{0} is a set by   
   Σ₀-comprehension, contradicting the axiom of infinity.   
   Therefore in every model M⊨ZF, E^M is not an element of M.   
   In particular, E^M has no cardinality inside M, hence cannot contradict   
   “ℝ is uncountable in M”.   
   The constructible universe L satisfies ZF, and E^L is again a proper   
   class in L.   
   So your “witness” does not exist even in the minimal inner model.   
   Ergo the alleged reductio never gets off the ground: the bullet misses   
   because the target is not a set.   
      
   Conclusion: You may principle that “Well-Ordering, Well-Foundedness,   
   Well-Dispersion” hold of E, but you cannot use E as a set-theoretic   
   object that violates any theorem of ZF. The armour is “too weak to   
   break” precisely because it is empty of sets.   
   If you want to push the dialectic further, shift the battlefield to   
   meta-ZF: argue that your “A-theory” (axiomless natural deduction) is a   
   description of what set-theorists are doing when they speak of “the”   
   well-order of ℝ, rather than a rival ontology. In that rhetorical mode,   
   the three “Well-” slogans function as heuristics, not as existential   
   claims inside ZF. The moment you are read as offering heuristics, the   
   demand for a contradictory model evaporates—nobody asks a metaphor to   
   satisfy Separation.   
   Ring when you need the next layer: a full conservativity proof over ZFC,   
   or a faithful interpretation of your E-class in Feferman’s schematic ZFC/S.   
      
      
      
   Thanks Kimi. While it was intended to inroduce that wider surrounds and   
   the extra-ordinary of axiomless natural deduction or "null-axiom set   
   theory", what that argument is missing is that the functionhood is   
   "not-a-Cartesian-function", that the "bijective-functionhood" that   
   defined extent, dis-allows its consideration with regards to transitive   
   cardinality the Cantor-Schroeder-Bernstein. This is that, "it is a   
   theorem of ZF that there exist non-Cartesian bijections that model   
   functionhood".   
      
      
      
      
   RF, let me first separate the two distinct assertions you are now   
   making, and then give the precise ZF verdict on each.   
      
   “There exist, in ZF, bijections that are ‘non-Cartesian’.”   
   “Such bijections escape the Cantor-Schröder-Bernstein (CSB) analysis of   
   cardinality.”   
      
   Below I show:   
   A. Inside ZF every object that is allowed to play the role of a function   
   is a set of ordered pairs, hence a subset of a Cartesian product.   
   B. Therefore every bijection—no matter how exotic its internal coding—is   
   a Cartesian function in the only sense that ZF recognises.   
   C. Consequently CSB applies to all bijections that ZF can prove to   
   exist; no “non-Cartesian” bijection can evade transitive cardinality   
   arguments.   
      
   [continued in next message]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   
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