Do you need a default class for the rule set?

No because every instance is guaranteed to trigger at least

one rule.Consider a binary classification problem with the following set of attributes

and attribute values:

• Air Conditioner = {Working, Broken}

• Engine = {Good, Bad}

• Mileage = {High, Medium, Low}

• Rust = {Yes, No}

Suppose a rule-based classifier produces the following rule set:

No because every instance is guaranteed to trigger at least
one rule.