General-to-Specific Ordering

• By taking advantage of naturally occurring structure, we can design learning algorithms that exhaustively search even infinite hypothesis spaces without explicitly enumerating every hypothesis.
• For instance, general-to-specific ordering
  
  
• Any instance classified positive by will be classified positive by , therefore is more general than .
• Let and be boolean-valued functions defined over X. Then is more-general-than-or-equal-to if and only if
• More-general-than and more-specific-than are also useful.