SLIDE 61 ◆♦t❛t✐♦♥s ❛♥❞ ❉❡✜♥✐t✐♦♥s ▼✐♥✐♠❛❧ ❆r✐t② ♦❢ ◆❯ ❈r✐t❡r✐❛ ♦❢ ❊①✐st❡♥❝❡ ◆❯ Pr♦♦❢ ❢♦r t❤❡ ■❞❡♠♣♦t❡♥t ❈❛s❡
❙t❡♣ ✶ C ❝♦♥t❛✐♥s ❛ ◆❯ ♦❢ ❛r✐t② n + 1 ❜✉t ♥♦t n✳ ❲❡ ❦♥♦✇ ❢r♦♠ ❆❆❆✽✼
✶ ❆ ❝❧♦♥❡ C ❞♦❡s♥✬t ❝♦♥t❛✐♥ ❛ ◆❯ ♦❢ ❛r✐t② n ✐✛ t❤❡r❡ ❡①✐sts ❛
❝♦♠♣❛t✐❜❧❡ ❦❡② ✭❝r✐t✐❝❛❧✮ r❡❧❛t✐♦♥ ♦❢ ❛r✐t② n✳
✷ ❋♦r ❛♥② ❦❡② r❡❧❛t✐♦♥ ρ ♣r❡s❡r✈❡❞ ❜② ❛ ◆❯ ✇❡ ❝❛♥ ✜♥❞
(a1, a2, . . . , an) / ∈ ρ s✉❝❤ t❤❛t ({a1, b1} × {a2, b2} × · · · × {an, bn}) \ {(a1, a2, . . . , an)} ⊆ ρ. ❚❤✉s✱ ✇❡ ❤❛✈❡ ρ ♣r❡s❡r✈❡❞ ❜② C✱ (a1, a2, . . . , an) / ∈ ρ ❛♥❞ ({a1, b1} × {a2, b2} × · · · × {an, bn}) \ {(a1, a2, . . . , an)} ⊆ ρ. (a1, . . . , an) / ∈ ({a1, b1} × · · · × {an, bn}) \ {(a1, . . . , an)}C. ❲❡ ❝♦♥s✐❞❡r ✐❞❡♠♣♦t❡♥t ❝❛s❡✦ ❲❡ ❝❤♦♦s❡ t❤❡ ♠♦st ♣♦♣✉❧❛r ♣❛✐r (ai, bi) t♦ ❣❡t {a}n1 / ∈ {a, b}n1 \ {a}n1C ❢♦r n1 ≥ n/|A|2✳