Concept learning : disjunctive hypothesis space

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In my concept learning problem, three are 3 attributes (size,color,shape). Each attribute has 3 features showed in the picture below.

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In the conjunctive rule learning, hypotheses are like this:

  • (big,red,?) means two constraints on size and color, but no constraint on shape
  • (?,?,?) means no constraint for all features
  • ( $\varnothing$,$\varnothing$,$\varnothing$ ) means no value is acceptable

Assume hypothesis function noted by $~z=(a_i,b_i,c_i)~$, there are $3^3+1=28$ potential hypotheses.

Now consider the disjunctive rule. The hypothesis function is noted by $h=z_1\lor z_2\lor z_3...\lor z_k$ , with k conjunctive sub-hypothesis.

In view of disjunctive way , $(small,?,circle)\lor (large,red,?)$ is a new hypothesis with two conjunctive sub-hypothesis.

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The final question is:

Assume k is the max number of conjunctive sub-hypothesis in all disjunctive hypotheses, what's the hypothesis space or how many potential hypotheses there are ?

PS: Equivalent hypotheses should be considered as $1$ hypothesis.

In the case of

$$ \begin{align} h_1&=(big,?,?)\lor (big,red,?) \\ h_2&=(big,?,?) \end{align} $$ ,the two hypotheses are equivalent, they can be described as $h=(big,?,?)$.


We know when $k=1$, the problem is converted to conjunctive way, there are

$3^3+1=28$ potentials hypotheses.

When $k=2,3,4...$,what's the solution ?