SLIDE 54 ❙t✉❞② ♦❢ t❤❡ ■❚❊P
◮ ❉❡✜♥❡ ♦♥ X × X t❤❡ s❡sq✉✐❧✐♥❡❛r ❢♦r♠ a((u, w), (u′, w′)) =
A∇u · ∇u′ ✲ ∇w · ∇w′ − k2(nuu′ ✲ ww′), ✇✐t❤ X = {(u, w) ∈ H1(Ω) × H1(Ω) | u − w ∈ H1
0(Ω)}✳
◮ ■♥tr♦❞✉❝❡ t❤❡ ✐s♦♠♦r♣❤✐s♠ ❚(u, w) = (u − 2w, −w)✳ ◮ ❋♦r k ∈ Ri\{0}✱ A > Id ❛♥❞ n > 1✱ ♦♥❡ ✜♥❞s ℜe a((u, w), ❚(u, w)) ≥ C (u2
H1(Ω) + w2 H1(Ω)),
∀(u, w) ∈ X. ◮ ❯s✐♥❣ t❤❡ ❛♥❛❧②t✐❝ ❋r❡❞❤♦❧♠ t❤❡♦r❡♠✱ ♦♥❡ ❞❡❞✉❝❡s t❤❡ Pr♦♣♦s✐t✐♦♥✳ ❙✉♣♣♦s❡ t❤❛t A > Id ❛♥❞ n > 1✳ ❚❤❡♥ t❤❡ s❡t ♦❢ tr❛♥s♠✐s✲ s✐♦♥ ❡✐❣❡♥✈❛❧✉❡s ✐s ❞✐s❝r❡t❡ ❛♥❞ ❝♦✉♥t❛❜❧❡✳ ◮ ❚❤✐s r❡s✉❧t ❝❛♥ ❜❡ ❡①t❡♥❞❡❞ t♦ s✐t✉❛t✐♦♥s ✇❤❡r❡ A − Id ❛♥❞ n − 1 ❝❤❛♥❣❡ s✐❣♥ ✐♥ Ω ✇♦r❦✐♥❣ ✇✐t❤ ❚(u, w) = (u − 2χw, w)✮✳
✶✷ ✴ ✶✺