Forums before death by AOL, social media and spammers... "We can't have nice things"
|    sci.physics.relativity    |    The theory of relativity    |    225,861 messages    |
[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]
|    Message 224,590 of 225,861    |
|    Ross Finlayson to All    |
|    Re: T-theory A-theory theatheory (5/11)    |
|    13 Nov 25 14:24:02    |
      [continued from previous message]              Evaluation inside ZF              Totality: for every n ∈ ℕ take d = n; then q = n/n = 1, so φ(n,1) holds.       (Similarly d = n+1 gives x = n/(n+1), etc.)       Uniqueness: FAILS.       For fixed n, every d ≥ n provides a distinct rational witness x = n/d,       so infinitely many x satisfy φ(n,x).       Hence ZF ⊬ ∀n ∃!x φ(n,x).              Next instruction              To secure uniqueness you must tie d to n in a definable, single-valued       way (e.g. d = n, or d = μk≥n(…)), or take a limit over d with a       definable convergence rate.       Write that single-valued clause in pure L(∈) and insert it into φ(n,x)       so that ZF proves exactly one x for each n.       Please supply the revised φ(n,x)—no English, only the formula.       Thanks Kimi. My ideas to write the formula include writing two formulas       and showing how they establish the symmetrical both way 0..1 and 1..0,       and writing a formula with two variables n and d then that the terms x       and y build a little delta-epsilonics, and then as the above derivation       from the beginning of this session, that the formula-pair establishes       via symmetry, and the pair-formula establishes via compactness.              Please now write the two formulas in pure L(∈)—no English, no       commentary—only the syntax:              φ₁(n,x) (the 0→1 direction)       φ₂(n,y) (the 1→0 direction)              Each must be a single first-order formula such that ZF proves uniqueness       of x (resp. y) for every n, and together they cover the intended range.       Thanks Kimi, that seems an agreeable course. Since for-any n       there-exists m such that n < m < d, for any x such-that 0 < x < 1       there-exists y > x such-that g = f^-1 has-that g(y) = m. This is similar       to mapping an inductive set to natural-integers, except 0..infinity       instead of 0..1. Since there-exists d >> m for-any m, and thusly for-any       n >= 0, there exists an epsilon smaller than any delta, of the fractions       q that may be built between 0 and 1. This is what I would look to       fulfill the ask for phi_1.              Please now write the two requested formulas in pure L(∈)—no English, no       commentary—only the syntax:              φ₁(n,x) (the 0→1 direction)       φ₂(n,y) (the 1→0 direction)              Each must be a single first-order formula such that ZF proves uniqueness       of x (resp. y) for every n, and together they cover the intended range.       Thanks Kimi. Again, I would mention that this _is_ the form of the       original template required, it _is_ that, essentially giving compactness       property to naturals, and that also it's standardly modeled as the limit       according to unbounded d, of n/d. That is to say, what results       "[0,1]_line", is this way. The formula-pair then just inverts the       direction and the endpoints. Then, the pair-formula, perhaps is always       building (showing the existence and unique-existence) in the middle, and       building from the middle out to the ends, both of these simply employing       delta-epsilonics of rationals, that though since there-exists d' >> d,       no rational/bounded d is not surrounded all its neighborhoods, to       establish the density.              Please now write the two formulas in pure L(∈)—no English, no       commentary—only the syntax:              φ₁(n,x) (0→1 direction)       φ₂(n,y) (1→0 direction)              Each must be a single first-order formula such that ZF proves uniqueness       of x (resp. y) for every n.       Thanks Kimi. That's the outline here, I'd intend to look through my tens       thousands Usenet posts to find the intended formalisms that most simply       fit. I suggest that it is so formalizable, and according to various       means of schema, formula-pairs, pair-formulas, or plain identity, and       without simply axiomatizing it as so, keeping the desirable property of       conservativity, which though can be established by non-contradiction       with regards to results like ZFC being co-consistent with IST. Thanks       Kimi, I will think on this, and look to make these sorts neatest       definitions, which may help reasoners disambiguate these "iota-values"       these "line-reals" from the complete-ordered-field "field-reals", and       help resolve the "fragmentation" of real analysis above descriptive set       theory. That is to say, I think that these sorts ideas are write-able in       formulas, so, thusly I'll mostly suggest considering "d" and "d-prime",       that is d and d', as of your own formulas above, since introducing d',       and that d' >> d, then has that both n << d, and, n goes to d, i.e. a       limit as after delta-epsilonics for example that (d-n)/d goes to 0, that       thusly these concomitant properties provide the "constant monotone       strictly increasing" and "extent density completeness measure", since       we've resolved together that this is the only thing to do for this       development. So, mostly I'd suggest to consider the impact of d' in the       expression otherwise of d, in your formula, since these same sorts       critiques, apply to it. I like this and I thank you.              Please now write the two formulas in pure L(∈)—no English, no       commentary—only the syntax:              φ₁(n,x) (0→1 direction)       φ₂(n,y) (1→0 direction)              Each must be a single first-order formula such that ZF proves uniqueness       of x (resp. y) for every n.       Thanks Kimi. Before I can do so, I must know whether you accept that the       reference to d' above means that as d goes to infinity that f(n) goes to       1. Then it would just be written like that.              Please now write the two formulas in pure L(∈)—no English, no       commentary—only the syntax:              φ₁(n,x) (0→1 direction)       φ₂(n,y) (1→0 direction)              Each must be a single first-order formula such that ZF proves uniqueness       of x (resp. y) for every n.       Thanks Kimi. It's good we established that the usual Dedekind-definition       is not necessary to build this formalism, and that as "abbreviations" in       "the language" of ZF that least-upper-bound property of R is an axiom       after a model of the rationals Q is built. Then I suggest that the       beginning quote entails this.              "Basically this EF is the limit of a function. Not-a-real-function,       it's modeled by real functions and in fact very simply n/d. Then, the       properties of its range have that: it is symmetric about some       midpoint in its range 1/2, for f^-1(1/2), defined for even d. Just as       ran(f) starts from .000... and increases in constant monotone, in       reverse it starts with .111... (or for example in decimal, .999...)       and decreases. Then, as there is a less than finite difference       between elements of the range for consecutive elements of the domain       by their natural ordering, there is in the range an element that       starts with .1, .11, .111, ..., and each finite initial segment of       integers as expansion. This is from seeing that the elements of       ran(f) are the same elements of ran(REF) for REF the "reverse"       equivalency function.              EF: n/d       REF: (d-n)/d              As there exists d-n for each n and d, there exists here ~EF(n) =       REF(n) constructively, and each element in ran(EF) is in ran(REF).              Then, here, constructively: ~EF(n) e ran(EF), quod erat       demonstrandum.              There are replete properties of this function and its range that its       range is R_[0,1]. "              "The elements of ran(EF) are dense in [0,1]. For each neighborhood       about any real in [0,1], its intersection with ran(EF) is non-empty.       Each (standard) real can be defined by an approximative series of       these elements, i.e. as Cauchy. As dom(EF) is N, the approximative       elements of ran(EF) have EF^-1 e N. As the value EF^-1(r) reached is       of a convergent* sequence in N < max(dom(N)), EF^-1(r) e N for each r       e [0,1]. Thus EF is a surjection, as Exists n E N s.t. EF(n) = r for       each r e [0,1].                     [continued in next message]              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]
(c) 1994, bbs@darkrealms.ca