Forums before death by AOL, social media and spammers... "We can't have nice things"
|    sci.logic    |    Logic -- math, philosophy & computationa    |    262,912 messages    |
[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]
|    Message 262,910 of 262,912    |
|    olcott to Richard Damon    |
|    Re: Making all knowledge expressed in la    |
|    19 Feb 26 21:34:02    |
      XPost: comp.theory, sci.math       From: polcott333@gmail.com              On 2/19/2026 8:44 PM, Richard Damon wrote:       > On 2/19/26 6:47 AM, polcott wrote:       >> On 2/19/2026 4:06 AM, Mikko wrote:       >>> On 18/02/2026 21:48, polcott wrote:       >>>> On 2/18/2026 3:10 AM, Mikko wrote:       >>>>> On 17/02/2026 14:59, polcott wrote:       >>>>>> On 2/17/2026 3:03 AM, Mikko wrote:       >>>>>>> On 16/02/2026 15:47, olcott wrote:       >>>>>>>> On 2/16/2026 5:25 AM, Mikko wrote:       >>>>>>>>> On 15/02/2026 15:02, polcott wrote:       >>>>>>>>>> ∀x ∈ PA (True(PA, x) ↔ PA ⊢ x)       >>>>>>>>>> Does not mean to test every x in PA       >>>>>>>>>       >>>>>>>>> No, it merely declares that there are two symbols for one       >>>>>>>>> predicate       >>>>>>>>> (which, if interpreted accordint to the usual meaning of either       >>>>>>>>> symbol,       >>>>>>>>> is uncomputable).       >>>>>>>>       >>>>>>>> What do you think that this means: PA ⊢ x ?       >>>>>>>       >>>>>>> The exact meaning depends on the context and the meanings of the       >>>>>>> types of the left and right side expressions. The usual       >>>>>>> metalogical meaning       >>>>>>> is that x is a theorem of some variant of PA. If something else is       >>>>>>> meant that should be specified in the opus where the expression       >>>>>>> is used       >>>>>>       >>>>>> Yes that is correct. What does that mean?       >>>>>       >>>>> It means that the author must define the symbols in the opus they are       >>>>> used.       >>>>       >>>> Is this your best answer or are you trying to be evasive?       >>>       >>> Whether another answer would be better is a matter of taste, at least       >>> to some extent.       >>>       >>       >> PA ⊢ x       >> The correct answer is       >> A back-chained inference from x to the axioms of PA exists       >>       >       > No, that is *ONE* definition of it, but in other contexts, it might mean       > something different.       >       > All you are doing is proving you don't understand the importance of       > context for definitions.       >       > In fact, I rarely hear about it specifing that a "back chain" exists,       > instead it normally is described as there exists a "proof" of x in PA.       >       > Proofs, are more normally talked about as something that moves in the       > FORWARD direction, from the axioms of the system to the conclusion, not       > about "back-chaining".       >       >              That is correct              --       Copyright 2026 Olcott |
[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]
(c) 1994, bbs@darkrealms.ca