What about Cyc? It operates on a taxonomy (graph) which is a highly complex 
topology.
~PM

Date: Mon, 22 Jun 2015 18:57:05 -0700
From: [email protected]
To: [email protected]
Subject: Re: [agi] Re: Could Brain Emulation be NP-Hard?


  
    
  
  
    I seldom ask this as I usually work at the level of abstractions. 
    But could you please give some examples of topological relationships
    that are difficult to express computationally?  I am not sure I
    follow exactly what you have in mind.  

    

    Thanks.

    

    - samantha

    

    

    On 06/16/2015 06:09 PM, J. Andrew
      Rogers wrote:

    
    
      
      

      
        
          On Jun 16, 2015, at 3:26 PM, Dean Pomerleau <[email protected]> 
wrote: 
          
            
              
                In short, growing
                    evidence supporting the importance of cortical
                    oscillations in neural processing suggests that this
                    sort of analog/digital feedback loop might be
                    critical to how the brain works, and that such
                    interactions might be very hard (possible
                    intractably hard) to model accurately (i.e.
                    emulation vs. merely crude simulation) on a digital
                    computer, in a similar way to how protein folding is
                    intractable to model on a digital computer.   
              
            
          
        
        

      
      

      
      The tractability challenges of computational dynamics for
        brain-like models is related to why we can’t analyze the
        dynamics of *any* non-trivial physical world system. It is not
        coincidence that all “big data” computation focuses solely on
        relationships in the electronic world and not the physical
        world.
      

      
      Interestingly, computer scientists rarely notice that these
        software systems do not exist until you point it out. And when
        you do point it out they are at a loss to explain why. It is
        only “obvious” in hindsight.
      

      
      

      
      Virtually all existing computer science is based on the
        manipulation of graph-like data models and primitives. The
        problem is that some systems, notably physical world systems,
        have relationships that are fundamentally topological in nature.
        Graphs are a special, strict subset of more general topological
        computing representations; it is not possible to construct a
        scalable topological computational model on top of graph
        primitives.
      

      
      There is no computer science literature for computing on
        topological data models. To the extent algorithms and data
        structures exist to handle basic topological data models (e.g.
        R-trees), they exhibit pathological scalability because they are
        shoehorned into traditional graph models. If you want to compute
        on topological models at scale, you need to build a completely
        new computer science stack, from the most elementary primitives
        on up. And it needs to have an efficient implementation on
        conventional silicon.
      

      
      

      
      If you can directly manipulate topologies as computational
        constructs, instead of graphs only, many types of computational
        dynamic suddenly become *much* more tractable. In practice, the
        use of inappropriate algorithms and data structures to represent
        topological relationships are responsible for most
        intractability related to expressions of physical world system
        dynamics on a computer. It just never crosses the mind of most
        computer scientists working on such things and it is never
        discussed in computer science curricula.
      

      
      

      
      
        
          
            
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