XPost: comp.theory, sci.math, comp.theory   
   From: rjh@cpax.org.uk   
      
   On 15/12/2025 08:53, Mikko wrote:   
   > On 15/12/2025 02:31, olcott wrote:   
   >> Whenever any textbook says that a halt decider   
   >> must compute halting for machine M on input w   
   >> is it wrong. At best it only computes the halting   
   >> of M/w through the proxy of finite strings ⟨M⟩/w.   
   >>   
   >> Turing machine deciders compute the mapping from   
   >> input finite strings to an accept or reject value   
   >> by some criterion measure.   
   >>   
   >> Turing machine halt deciders compute the mapping   
   >> from input finite strings to a halt status on the   
   >> basis of the behavior that these finite strings   
   >> inputs actually specify.   
   >   
   > There are no halt deciders so they don't actually do anything.   
      
      
   Halt deciders are ten a penny.   
      
   This one, for example, works 99% of the time, +/-:   
      
   int halts(char *prgfilename, void *input)   
   {   
      return 1;   
   }   
      
   If you meant to claim that there are no *universal* halt   
   deciders, then of course I agree.   
      
   --   
   Richard Heathfield   
   Email: rjh at cpax dot org dot uk   
   "Usenet is a strange place" - dmr 29 July 1999   
   Sig line 4 vacant - apply within   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)