Approximation via Randomized Rounding

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• Approximation via Randomized Rounding
• Derandomizing Randomized Approximation

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Part I

• Approximation via (randomized) rounding

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Example 1 Deterministic rounding

• ???? (Vertex Cover)

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Vertex Cover Problem

• Input
• A graph G
• Output
• A smallest vertex subset of G that covers all
  edges of G.

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Illustration
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The Vertex Cover Problem is also NP-hard