Primal-Dual Method Primal: Dual: k k min B.x+ max yj j=1 j=1 s.t.x+zj≥1， j∈[k] x≥0，z1≥0， j∈[k] s.t. ∑ysB j= y∈[0,1]j x:the 'probability'of buying a ski Zi:the 'probability'of renting a ski at j-th round y:helping make decisionPrimal-Dual Method Primal: min 𝐵 ⋅ 𝑥 +෍ 𝑗=1 𝑘 𝑧𝑗 𝑠.𝑡. 𝑥 + 𝑧𝑗 ≥ 1, ∀𝑗 ∈ 𝑘 𝑥 ≥ 0, 𝑧𝑗 ≥ 0, ∀𝑗 ∈ 𝑘 Dual: max ෍ 𝑗=1 𝑘 𝑦𝑗 𝑠.𝑡. ෍ 𝑗=1 𝑘 𝑦𝑗 ≤ 𝐵 ∀𝑗 𝑦𝑗 ∈ [0,1] ∀𝑗 𝑥 : the ‘probability’ of buying a ski 𝑧𝑗 : the ‘probability’ of renting a ski at 𝑗-th round 𝑦𝑗 : helping make decision