• combinatorial explosion
  • even for a 5 state, 8x8 block image, the number of valid configurations is 5⁶⁴ = 5x10⁴⁴
  • can dynamic programming be used?
    
  • pruning can be employed
    
  • forward pass followed by backward pass could be employed
    
  
  
• can we use any hierarchical constraints here?
  • n-gram language models - P(B = SKY | B-1 = SKY, B-2 = SKY, ...) or grammars?
    
  • these are essentially an extension of the "neighborhood" for this task where paths not found in the grammar have a transition probability of zero
    
  • are there "sub-units" in this task?