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Lesson5.9. Candidate Elimination Algorithm

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  Consider the following dataset: Training Dataset A person named Aldo Enjoys sport under the given conditions. Concept The concept to learn is when does a person Aldo enjoy sports. The answer is Boolean : Yes – enjoys sport or No – doesn’t enjoy sport. Hypothesis Space The actual space in which we search is huge. So let us restrict to a hypothesis representation of the search space with only the attributes in the training dataset. The easiest way to represent is by taking the conjunction of all the attributes. That is, <sunny, warm, normal, strong, warm, same, yes> is a hypothesis represented by <x,c(x)>. Here c(x) is ‘yes’. We say that if it is, Sunny and warm and normal and strong and warm and same, then Aldo enjoys sports. Notations We assume the following notations as before: 0 – most specific and implies that the attribute should have no value. Attribute name – the given attributes in the table. Eg. sunny ? – the most generic where ...

Lesson5.8. List-then-eliminate Algorithm

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 Introduction The List-Then-Eliminate algorithm is a concept learning strategy used in machine learning and artificial intelligence to systematically search through a hypothesis space to find hypotheses that are consistent with a set of training examples. The algorithm operates under the principle of representational completeness, meaning it considers every possible hypothesis that can be constructed from the attributes in the training data.   At its core, the List-Then-Eliminate algorithm begins with the assumption that any hypothesis could be the true one, and it incrementally refines this set by eliminating any hypothesis that fails to correctly classify the training examples. It uses a version space approach, where the version space is defined as the subset of the hypothesis space that is consistent with all the observed training examples.   The algorithm can be summarized as follows:   1. Initialize Version Space:  Begin with a Version Space that contains e...