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r rt r t r - - PowerPoint PPT Presentation
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❆ t❛❧❦ ❛❜♦✉t ❢♦✉♥t❛✐♥s
- ♦❛❧✿ ❉❡s❝r✐❜❡ ❤♦✇ t❤❡ ❥❡t s❡♣❛r❛t❡s✳
✶ ✴ ✷✵
❆ t❛❧❦ ❛❜♦✉t ❢♦✉♥t❛✐♥s
- ♦❛❧✿ ❉❡s❝r✐❜❡ ❤♦✇ t❤❡ ❥❡t s❡♣❛r❛t❡s✳
✶ ✴ ✷✵
❏❡ts
■♥❝♦♠♣r❡ss✐❜✐❧✐t②✿ ❊①✐sts str❡❛♠ ❢✉♥❝t✐♦♥ s✉❝❤ t❤❛t ✈❡❧♦❝✐t② ■rr♦t❛t✐♦♥❛❧✐t②✿ ❇❡r♥♦✉❧❧✐✬s ❧❛✇✿ ✭ ♦r ✮ ♦✈❡r
✷ ✴ ✷✵
❏❡ts
■♥❝♦♠♣r❡ss✐❜✐❧✐t②✿ ❊①✐sts str❡❛♠ ❢✉♥❝t✐♦♥ u ≥ 0 s✉❝❤ t❤❛t ✈❡❧♦❝✐t② = Du⊥ = (∂2u, −∂1u) ■rr♦t❛t✐♦♥❛❧✐t②✿ ❇❡r♥♦✉❧❧✐✬s ❧❛✇✿ ✭ ♦r ✮ ♦✈❡r
✷ ✴ ✷✵
❏❡ts
■♥❝♦♠♣r❡ss✐❜✐❧✐t②✿ ❊①✐sts str❡❛♠ ❢✉♥❝t✐♦♥ u ≥ 0 s✉❝❤ t❤❛t ✈❡❧♦❝✐t② = Du⊥ = (∂2u, −∂1u) ■rr♦t❛t✐♦♥❛❧✐t②✿ ∆u = 0 ❇❡r♥♦✉❧❧✐✬s ❧❛✇✿ ✭ ♦r ✮ ♦✈❡r
✷ ✴ ✷✵
❏❡ts
■♥❝♦♠♣r❡ss✐❜✐❧✐t②✿ ❊①✐sts str❡❛♠ ❢✉♥❝t✐♦♥ u ≥ 0 s✉❝❤ t❤❛t ✈❡❧♦❝✐t② = Du⊥ = (∂2u, −∂1u) ■rr♦t❛t✐♦♥❛❧✐t②✿ ∆u = 0 ❇❡r♥♦✉❧❧✐✬s ❧❛✇✿ |Du| = 1 ✭Du = −ν ♦r ∂νu = −1✮ ♦✈❡r Γ+
✷ ✴ ✷✵
❖♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠
u ≥ 0 s❛t✐s✜❡s
- ∆u = 0 ✐♥ Ω+ = {u > 0} ∩ Ω
|Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ Ω ❆❧t✲❈❛✛❛r❡❧❧✐ ✶✾✽✶✿ ■♥t❡r✐♦r r❡s✉❧ts ❤❛s ❧♦❝❛❧ ✜♥✐t❡ ♣❡r✐♠❡t❡r ✐s r❡❣✉❧❛r ♣r♦✈✐❞❡❞ ❛ ✢❛t♥❡ss ❤②♣♦t❤❡s✐s
✸ ✴ ✷✵
❖♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠
u ≥ 0 s❛t✐s✜❡s
- ∆u = 0 ✐♥ Ω+ = {u > 0} ∩ Ω
|Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ Ω ❆❧t✲❈❛✛❛r❡❧❧✐ ✶✾✽✶✿ ■♥t❡r✐♦r r❡s✉❧ts ❤❛s ❧♦❝❛❧ ✜♥✐t❡ ♣❡r✐♠❡t❡r ✐s r❡❣✉❧❛r ♣r♦✈✐❞❡❞ ❛ ✢❛t♥❡ss ❤②♣♦t❤❡s✐s
✸ ✴ ✷✵
❖♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠
u ≥ 0 s❛t✐s✜❡s
- ∆u = 0 ✐♥ Ω+ = {u > 0} ∩ Ω
|Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ Ω ❆❧t✲❈❛✛❛r❡❧❧✐ ✶✾✽✶✿ ■♥t❡r✐♦r r❡s✉❧ts ◮ u ∈ C0,1
loc
❤❛s ❧♦❝❛❧ ✜♥✐t❡ ♣❡r✐♠❡t❡r ✐s r❡❣✉❧❛r ♣r♦✈✐❞❡❞ ❛ ✢❛t♥❡ss ❤②♣♦t❤❡s✐s
✸ ✴ ✷✵
❖♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠
u ≥ 0 s❛t✐s✜❡s
- ∆u = 0 ✐♥ Ω+ = {u > 0} ∩ Ω
|Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ Ω ❆❧t✲❈❛✛❛r❡❧❧✐ ✶✾✽✶✿ ■♥t❡r✐♦r r❡s✉❧ts ◮ u ∈ C0,1
loc
◮ Ω+ ❤❛s ❧♦❝❛❧ ✜♥✐t❡ ♣❡r✐♠❡t❡r ✐s r❡❣✉❧❛r ♣r♦✈✐❞❡❞ ❛ ✢❛t♥❡ss ❤②♣♦t❤❡s✐s
✸ ✴ ✷✵
❖♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠
u ≥ 0 s❛t✐s✜❡s
- ∆u = 0 ✐♥ Ω+ = {u > 0} ∩ Ω
|Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ Ω ❆❧t✲❈❛✛❛r❡❧❧✐ ✶✾✽✶✿ ■♥t❡r✐♦r r❡s✉❧ts ◮ u ∈ C0,1
loc
◮ Ω+ ❤❛s ❧♦❝❛❧ ✜♥✐t❡ ♣❡r✐♠❡t❡r ◮ Γ+ ✐s C1,α r❡❣✉❧❛r ♣r♦✈✐❞❡❞ ❛ ✢❛t♥❡ss ❤②♣♦t❤❡s✐s
✸ ✴ ✷✵
❏❡ts ❛♥❞ ❝❛✈✐t✐❡s
u ≥ 0 s❛t✐s✜❡s
- ∆u = 0 ✐♥ Ω+ = {u > 0} ∩ Ω
|Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ Ω ❙❧✐♣ ❝♦♥❞✐t✐♦♥✿ ♦✈❡r ❍♦✇ ❞♦❡s ❞❡t❛❝❤ ❢r♦♠ ❄
✹ ✴ ✷✵
❏❡ts ❛♥❞ ❝❛✈✐t✐❡s
u ≥ 0 s❛t✐s✜❡s
- ∆u = 0 ✐♥ Ω+ = {u > 0} ∩ Ω
|Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ Ω ❙❧✐♣ ❝♦♥❞✐t✐♦♥✿ u = 0 ♦✈❡r Z = {x2 > 0} ❍♦✇ ❞♦❡s Γ ❞❡t❛❝❤ ❢r♦♠ Z❄
✹ ✴ ✷✵
❘❡❣✉❧❛r✐t② ♦❢ Γ ✉♣ t♦ t❤❡ ✭✜①❡❞✮ ❜♦✉♥❞❛r②
❚❤❡♦r❡♠ ✭❈✲❙❛✈✐♥✮
▲❡t Ω ⊆ Rn ❜❡ ❛ ❞♦♠❛✐♥ ✇✐t❤ ❛ C1,α ❜♦✉♥❞❛r② ♣♦rt✐♦♥ Z ⊆ ∂Ω ✇✐t❤ α > 1/2✳ ▲❡t u ≥ 0 ❜❡ ❛ ✭✈✐s❝♦s✐t②✮ s♦❧✉t✐♦♥ ♦❢ ∆u = 0 ✐♥ Ω+ = {u > 0} ∩ Ω |Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ Ω u = 0 ♦♥ Z |Du| ≥ 1 ♦♥ Γ0 = ∂Ω+ ∩ Z ❚❤❡♥ Γ = Γ+ ∪ Γ0 ✐s C1,1/2 r❡❣✉❧❛r ♦♥ ❛ ♥❡✐❣❤❜♦r❤♦♦❞ ♦❢ ❡✈❡r② x0 ∈ Γ0✳
✺ ✴ ✷✵
❘❡❣✉❧❛r✐t② ♦❢ Γ ✉♣ t♦ t❤❡ ✭✜①❡❞✮ ❜♦✉♥❞❛r②
❚❤❡♦r❡♠ ✭❈✲❙❛✈✐♥✮
▲❡t Ω ⊆ Rn ❜❡ ❛ ❞♦♠❛✐♥ ✇✐t❤ ❛ C1,α ❜♦✉♥❞❛r② ♣♦rt✐♦♥ Z ⊆ ∂Ω ✇✐t❤ α > 1/2✳ ▲❡t u ≥ 0 ❜❡ ❛ ✭✈✐s❝♦s✐t②✮ s♦❧✉t✐♦♥ ♦❢ ∆u = 0 ✐♥ Ω+ = {u > 0} ∩ Ω |Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ Ω u = 0 ♦♥ Z |Du| ≥ 1 ♦♥ Γ0 = ∂Ω+ ∩ Z ❚❤❡♥ Γ = Γ+ ∪ Γ0 ✐s C1,1/2 r❡❣✉❧❛r ♦♥ ❛ ♥❡✐❣❤❜♦r❤♦♦❞ ♦❢ ❡✈❡r② x0 ∈ Γ0✳
✺ ✴ ✷✵
✭ ¯ F = Γ✮
✻ ✴ ✷✵
|Du| ≥ 1 ♦♥ Γ0❄
❚❤❡ ♦♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠ ❛r✐s❡s ❛s t❤❡ ❊✉❧❡r✲▲❛❣r❛♥❣❡ ❡q✉❛t✐♦♥ ♦❢ ✐♥ ❋♦r ❛ ❞♦♠❛✐♥ ✈❛r✐❛t✐♦♥ ❚❤✐s ✐♠♣❧✐❡s ♦♥ ❲❡ ❛r❡ ❛❧s♦ ❛❧❧♦✇ t♦ ♣❡r❢♦r♠ ✐♥✇❛r❞ ❞❡❢♦r♠❛t✐♦♥s ❛r♦✉♥❞ ♦♥
✼ ✴ ✷✵
|Du| ≥ 1 ♦♥ Γ0❄
❚❤❡ ♦♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠ ❛r✐s❡s ❛s t❤❡ ❊✉❧❡r✲▲❛❣r❛♥❣❡ ❡q✉❛t✐♦♥ ♦❢ min{Ju : u = g ≥ 0 ✐♥ ∂Ω} Ju = ˆ
Ω
|Du|2 + χ{u>0} ❋♦r ❛ ❞♦♠❛✐♥ ✈❛r✐❛t✐♦♥ ❚❤✐s ✐♠♣❧✐❡s ♦♥ ❲❡ ❛r❡ ❛❧s♦ ❛❧❧♦✇ t♦ ♣❡r❢♦r♠ ✐♥✇❛r❞ ❞❡❢♦r♠❛t✐♦♥s ❛r♦✉♥❞ ♦♥
✼ ✴ ✷✵
|Du| ≥ 1 ♦♥ Γ0❄
❚❤❡ ♦♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠ ❛r✐s❡s ❛s t❤❡ ❊✉❧❡r✲▲❛❣r❛♥❣❡ ❡q✉❛t✐♦♥ ♦❢ min{Ju : u = g ≥ 0 ✐♥ ∂Ω} Ju = ˆ
Ω
|Du|2 + χ{u>0} ❋♦r ❛ ❞♦♠❛✐♥ ✈❛r✐❛t✐♦♥ uε(x + εη(x)) = u(x) Juε = Ju + ε ˆ
Γ
(1 − |Du|2)η · ν + o(ε) ❚❤✐s ✐♠♣❧✐❡s |Du| = 1 ♦♥ Γ+ ❲❡ ❛r❡ ❛❧s♦ ❛❧❧♦✇ t♦ ♣❡r❢♦r♠ ✐♥✇❛r❞ ❞❡❢♦r♠❛t✐♦♥s ❛r♦✉♥❞ ♦♥
✼ ✴ ✷✵
|Du| ≥ 1 ♦♥ Γ0❄
❚❤❡ ♦♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠ ❛r✐s❡s ❛s t❤❡ ❊✉❧❡r✲▲❛❣r❛♥❣❡ ❡q✉❛t✐♦♥ ♦❢ min{Ju : u = g ≥ 0 ✐♥ ∂Ω} Ju = ˆ
Ω
|Du|2 + χ{u>0} ❋♦r ❛ ❞♦♠❛✐♥ ✈❛r✐❛t✐♦♥ uε(x + εη(x)) = u(x) Juε = Ju + ε ˆ
Γ
(1 − |Du|2)η · ν + o(ε) ❚❤✐s ✐♠♣❧✐❡s |Du| = 1 ♦♥ Γ+ ❲❡ ❛r❡ ❛❧s♦ ❛❧❧♦✇ t♦ ♣❡r❢♦r♠ ✐♥✇❛r❞ ❞❡❢♦r♠❛t✐♦♥s ❛r♦✉♥❞ Z |Du| ≥ 1 ♦♥ Γ0
✼ ✴ ✷✵
|Du| ≥ 1 ♦♥ Γ0❄
❙♦❧✉t✐♦♥s ❝❛♥ ❛❧s♦ ❜❡ ❝♦♥tr❛st❡❞ ❜② P❡rr♦♥✬s ♠❡t❤♦❞✿ u ✐s t❤❡ s♠❛❧❧❡st s✉♣❡rs♦❧✉t✐♦♥ ❛❜♦✈❡ ❛ s✉❜s♦❧✉t✐♦♥ t❛❦✐♥❣ t❤❡ ❜♦✉♥❞❛r② ❞❛t✉♠ g ≥ 0✳ ❆❧s♦ ✐♥ t❤✐s s❡tt✐♥❣ ✇❡ r❡❝♦✈❡r ♦♥
✽ ✴ ✷✵
|Du| ≥ 1 ♦♥ Γ0❄
❙♦❧✉t✐♦♥s ❝❛♥ ❛❧s♦ ❜❡ ❝♦♥tr❛st❡❞ ❜② P❡rr♦♥✬s ♠❡t❤♦❞✿ u ✐s t❤❡ s♠❛❧❧❡st s✉♣❡rs♦❧✉t✐♦♥ ❛❜♦✈❡ ❛ s✉❜s♦❧✉t✐♦♥ t❛❦✐♥❣ t❤❡ ❜♦✉♥❞❛r② ❞❛t✉♠ g ≥ 0✳ ❆❧s♦ ✐♥ t❤✐s s❡tt✐♥❣ ✇❡ r❡❝♦✈❡r |Du| ≥ 1 ♦♥ Γ0
✽ ✴ ✷✵
Γ ∈ C1,1/2❄
▲❡t Ω = B+
1 ❛♥❞ Z = B′ 1✳
❆ss✉♠✐♥❣ t❤❛t ❞❡t❛❝❤❡s ❢r♦♠ ❛t ✇❡ ❧❡t ✳ ❈❧❡❛r❧② ✐s ❤❛r♠♦♥✐❝ ✐♥ ✱ ❛♥❞ ♥♦♥♥❡❣❛t✐✈❡ ♦✈❡r ✳ ❍♦✇ ❞♦❡s t❤❡ ❢r❡❡ ❜♦✉♥❞❛r② ❝♦♥❞✐t✐♦♥ r❡✢❡❝t ♦♥ ❄ ♠❡❛♥s t❤❛t ♦♥ ❆❞❞✐t✐♦♥❛❧❧②✱ ♦♥ s❛②s t❤❛t ♦♥
✾ ✴ ✷✵
Γ ∈ C1,1/2❄
▲❡t Ω = B+
1 ❛♥❞ Z = B′ 1✳
❆ss✉♠✐♥❣ t❤❛t Γ ❞❡t❛❝❤❡s ❢r♦♠ Z ❛t 0 ✇❡ ❧❡t u = xn − εw ✳ ❈❧❡❛r❧② w ✐s ❤❛r♠♦♥✐❝ ✐♥ Ω+✱ ❛♥❞ ♥♦♥♥❡❣❛t✐✈❡ ♦✈❡r Γ✳ ❍♦✇ ❞♦❡s t❤❡ ❢r❡❡ ❜♦✉♥❞❛r② ❝♦♥❞✐t✐♦♥ r❡✢❡❝t ♦♥ w❄ ♠❡❛♥s t❤❛t ♦♥ ❆❞❞✐t✐♦♥❛❧❧②✱ ♦♥ s❛②s t❤❛t ♦♥
✾ ✴ ✷✵
Γ ∈ C1,1/2❄
▲❡t Ω = B+
1 ❛♥❞ Z = B′ 1✳
❆ss✉♠✐♥❣ t❤❛t Γ ❞❡t❛❝❤❡s ❢r♦♠ Z ❛t 0 ✇❡ ❧❡t u = xn − εw ✳ ❈❧❡❛r❧② w ✐s ❤❛r♠♦♥✐❝ ✐♥ Ω+✱ ❛♥❞ ♥♦♥♥❡❣❛t✐✈❡ ♦✈❡r Γ✳ ❍♦✇ ❞♦❡s t❤❡ ❢r❡❡ ❜♦✉♥❞❛r② ❝♦♥❞✐t✐♦♥ r❡✢❡❝t ♦♥ w❄ Du = −ν ♠❡❛♥s t❤❛t ∂nw = 1 ε(1 + νn) = ε 2|Dw|2 ♦♥ Γ+. ❆❞❞✐t✐♦♥❛❧❧②✱ |Du| ≥ 1 ♦♥ Γ0 s❛②s t❤❛t ∂nw ≥ 0 ♦♥ Γ0.
✾ ✴ ✷✵
Γ ∈ C1,1/2❄
❆s ε → 0✱ ✇❡ ❡①♣❡❝t Ω+ → B+
1 ✱ ❛♥❞ w t♦ s♦❧✈❡
∆w = 0 ✐♥ B+
1
w ≥ 0 ♦♥ B′
1
∂nw = 0 ♦♥ {w > 0} ∩ B′
1
∂nw ≤ 0 ♦♥ B′
1
❚❤❡ ❙✐❣♥♦r✐♥✐ ♦r t❤✐♥ ♦❜st❛❝❧❡ ♣r♦❜❧❡♠✦
❋✐❣✉r❡✿ ■♠❛❣❡ ❜② ❆rs❤❛❦ P❡tr♦s②❛♥
✶✵ ✴ ✷✵
Γ ∈ C1,1/2❄
❆s ε → 0✱ ✇❡ ❡①♣❡❝t Ω+ → B+
1 ✱ ❛♥❞ w t♦ s♦❧✈❡
∆w = 0 ✐♥ B+
1
w ≥ 0 ♦♥ B′
1
∂nw = 0 ♦♥ {w > 0} ∩ B′
1
∂nw ≤ 0 ♦♥ B′
1
❚❤❡ s❛♠❡ ❧✐♥❡❛r✐③❛t✐♦♥ ✐s ❢♦✉♥❞ ❛♥❞ ✉s❡❞ ❜② ❆♥❞❡rss♦♥✱ ❙❤❛❤❣❤♦❧✐❛♥✱ ❛♥❞ ❲❡✐ss✳ ❆t❤❛♥❛s♦♣♦✉❧♦s✲❈❛✛❛r❡❧❧✐ ✷✵✵✹✿ ✐s t❤❡ ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②✳ ■♥❞❡❡❞ ✐s ❛ s♦❧✉t✐♦♥✳ ❖✉r r❡s✉❧t s❛②s t❤❛t ✐♥❤❡r✐ts t❤❡ ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t② ♦❢ t❤❡ ❙✐❣♥♦r✐♥✐ ♣r♦❜❧❡♠✳
✶✶ ✴ ✷✵
Γ ∈ C1,1/2❄
❆s ε → 0✱ ✇❡ ❡①♣❡❝t Ω+ → B+
1 ✱ ❛♥❞ w t♦ s♦❧✈❡
∆w = 0 ✐♥ B+
1
w ≥ 0 ♦♥ B′
1
∂nw = 0 ♦♥ {w > 0} ∩ B′
1
∂nw ≤ 0 ♦♥ B′
1
❚❤❡ s❛♠❡ ❧✐♥❡❛r✐③❛t✐♦♥ ✐s ❢♦✉♥❞ ❛♥❞ ✉s❡❞ ❜② ❆♥❞❡rss♦♥✱ ❙❤❛❤❣❤♦❧✐❛♥✱ ❛♥❞ ❲❡✐ss✳ ❆t❤❛♥❛s♦♣♦✉❧♦s✲❈❛✛❛r❡❧❧✐ ✷✵✵✹✿ w ∈ C1,1/2 ✐s t❤❡ ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②✳ ■♥❞❡❡❞ w = r3/2 cos(3θ/2) ✐s ❛ s♦❧✉t✐♦♥✳ ❖✉r r❡s✉❧t s❛②s t❤❛t ✐♥❤❡r✐ts t❤❡ ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t② ♦❢ t❤❡ ❙✐❣♥♦r✐♥✐ ♣r♦❜❧❡♠✳
✶✶ ✴ ✷✵
Γ ∈ C1,1/2❄
❆s ε → 0✱ ✇❡ ❡①♣❡❝t Ω+ → B+
1 ✱ ❛♥❞ w t♦ s♦❧✈❡
∆w = 0 ✐♥ B+
1
w ≥ 0 ♦♥ B′
1
∂nw = 0 ♦♥ {w > 0} ∩ B′
1
∂nw ≤ 0 ♦♥ B′
1
❚❤❡ s❛♠❡ ❧✐♥❡❛r✐③❛t✐♦♥ ✐s ❢♦✉♥❞ ❛♥❞ ✉s❡❞ ❜② ❆♥❞❡rss♦♥✱ ❙❤❛❤❣❤♦❧✐❛♥✱ ❛♥❞ ❲❡✐ss✳ ❆t❤❛♥❛s♦♣♦✉❧♦s✲❈❛✛❛r❡❧❧✐ ✷✵✵✹✿ w ∈ C1,1/2 ✐s t❤❡ ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②✳ ■♥❞❡❡❞ w = r3/2 cos(3θ/2) ✐s ❛ s♦❧✉t✐♦♥✳ ❖✉r r❡s✉❧t s❛②s t❤❛t Γ = {xn = εw} ✐♥❤❡r✐ts t❤❡ ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t② ♦❢ t❤❡ ❙✐❣♥♦r✐♥✐ ♣r♦❜❧❡♠✳
✶✶ ✴ ✷✵
❙tr❛t❡❣②
❍❛r♥❛❝❦✲t②♣❡ ✐♥❡q✉❛❧✐t②✿ ❈♦♠♣❛❝t♥❡ss s♦ ✇❡ ❝❛♥ ❧✐♥❡❛r✐s❡✳ ❆❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ ❋♦r ✱ ❜② ❛ ❝♦♠♣❛❝t♥❡ss ❛r❣✉♠❡♥t✳ ❖♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ ❜② ❛♥ ❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛✳ ❋r♦♠ ♥♦✇ ♦♥ ✱ ❛♥❞ s❛t✐s✜❡s ✐♥ ♦♥ ♦♥ ♦♥
✶✷ ✴ ✷✵
❙tr❛t❡❣②
◮ ❍❛r♥❛❝❦✲t②♣❡ ✐♥❡q✉❛❧✐t②✿ ❈♦♠♣❛❝t♥❡ss s♦ ✇❡ ❝❛♥ ❧✐♥❡❛r✐s❡✳ ❆❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ ❋♦r ✱ ❜② ❛ ❝♦♠♣❛❝t♥❡ss ❛r❣✉♠❡♥t✳ ❖♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ ❜② ❛♥ ❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛✳ ❋r♦♠ ♥♦✇ ♦♥ ✱ ❛♥❞ s❛t✐s✜❡s ✐♥ ♦♥ ♦♥ ♦♥
✶✷ ✴ ✷✵
❙tr❛t❡❣②
◮ ❍❛r♥❛❝❦✲t②♣❡ ✐♥❡q✉❛❧✐t②✿ ❈♦♠♣❛❝t♥❡ss s♦ ✇❡ ❝❛♥ ❧✐♥❡❛r✐s❡✳ ◮ ❆❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ ❋♦r β ∈ (0, 1/2)✱ Γ ∈ C1,β ❜② ❛ ❝♦♠♣❛❝t♥❡ss ❛r❣✉♠❡♥t✳ ❖♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ ❜② ❛♥ ❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛✳ ❋r♦♠ ♥♦✇ ♦♥ ✱ ❛♥❞ s❛t✐s✜❡s ✐♥ ♦♥ ♦♥ ♦♥
✶✷ ✴ ✷✵
❙tr❛t❡❣②
◮ ❍❛r♥❛❝❦✲t②♣❡ ✐♥❡q✉❛❧✐t②✿ ❈♦♠♣❛❝t♥❡ss s♦ ✇❡ ❝❛♥ ❧✐♥❡❛r✐s❡✳ ◮ ❆❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ ❋♦r β ∈ (0, 1/2)✱ Γ ∈ C1,β ❜② ❛ ❝♦♠♣❛❝t♥❡ss ❛r❣✉♠❡♥t✳ ◮ ❖♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ Γ ∈ C1,1/2 ❜② ❛♥ ❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛✳ ❋r♦♠ ♥♦✇ ♦♥ ✱ ❛♥❞ s❛t✐s✜❡s ✐♥ ♦♥ ♦♥ ♦♥
✶✷ ✴ ✷✵
❙tr❛t❡❣②
◮ ❍❛r♥❛❝❦✲t②♣❡ ✐♥❡q✉❛❧✐t②✿ ❈♦♠♣❛❝t♥❡ss s♦ ✇❡ ❝❛♥ ❧✐♥❡❛r✐s❡✳ ◮ ❆❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ ❋♦r β ∈ (0, 1/2)✱ Γ ∈ C1,β ❜② ❛ ❝♦♠♣❛❝t♥❡ss ❛r❣✉♠❡♥t✳ ◮ ❖♣t✐♠❛❧ r❡❣✉❧❛r✐t②✿ Γ ∈ C1,1/2 ❜② ❛♥ ❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛✳ ❋r♦♠ ♥♦✇ ♦♥ Ω = B+
1 ✱ Z = B′ 1 ❛♥❞ u s❛t✐s✜❡s
∆u = 0 ✐♥ Ω+ = {u > 0} ∩ B+
1
|Du| = 1 ♦♥ Γ+ = ∂{u > 0} ∩ B+
1
u = 0 ♦♥ B′
1
|Du| ≥ 1 ♦♥ Γ0 = ∂Ω+ ∩ B′
1
✶✷ ✴ ✷✵
Pr❡❧✐♠✐♥❛r✐❡s✿ ❋r❡❡ ✢❛t♥❡ss
▲✐♥❡❛r ❜❡❤❛✈✐♦r ❛t r❡❣✉❧❛r ❜♦✉♥❞❛r② ♣♦✐♥ts✿ v ∈ C(Br)✱ ♥♦♥♥❡❣❛t✐✈❡✱ ❤❛r♠♦♥✐❝ ♦✈❡r Ω+ = {v > 0}✱ ❛♥❞ 0 ∈ ∂Ω+✳ ❆♥ ❡①t❡r✐♦r ❜❛❧❧ ❝♦♥❞✐t✐♦♥ ❢♦r Ω+ ❛t 0 ✐♠♣❧✐❡s v(x) = α(x · ν)+ + o(|x|) ❛s x ∈ Ω+ → 0 ♥♦♥t❛♥❣❡♥t✐❛❧❧② ■❢ ❞❡t❛❝❤❡s ❢r♦♠ ❛t ✱ t❤❡♥ ❛❢t❡r ❛ r❡s❝❛❧✐♥❣ ✇❡ ❝❛♥ ❛ss✉♠❡ ✐♥ ❢♦r ❛s s♠❛❧❧ ❛s ✇❡ ✇✐s❤✳
✶✸ ✴ ✷✵
Pr❡❧✐♠✐♥❛r✐❡s✿ ❋r❡❡ ✢❛t♥❡ss
▲✐♥❡❛r ❜❡❤❛✈✐♦r ❛t r❡❣✉❧❛r ❜♦✉♥❞❛r② ♣♦✐♥ts✿ v ∈ C(Br)✱ ♥♦♥♥❡❣❛t✐✈❡✱ ❤❛r♠♦♥✐❝ ♦✈❡r Ω+ = {v > 0}✱ ❛♥❞ 0 ∈ ∂Ω+✳ ❆♥ ❡①t❡r✐♦r ❜❛❧❧ ❝♦♥❞✐t✐♦♥ ❢♦r Ω+ ❛t 0 ✐♠♣❧✐❡s v(x) = α(x · ν)+ + o(|x|) ❛s x ∈ Ω+ → 0 ♥♦♥t❛♥❣❡♥t✐❛❧❧② ■❢ Γ ❞❡t❛❝❤❡s ❢r♦♠ Z ❛t 0✱ t❤❡♥ ❛❢t❡r ❛ r❡s❝❛❧✐♥❣ ✇❡ ❝❛♥ ❛ss✉♠❡ (1 + ε)xn ≥ u ≥ xn − ε ✐♥ B+
1
❢♦r ε > 0 ❛s s♠❛❧❧ ❛s ✇❡ ✇✐s❤✳
✶✸ ✴ ✷✵
❍❛r♥❛❝❦✲t②♣❡ ✐♥❡q✉❛❧✐t②
▲❡♠♠❛
❚❤❡r❡ ❡①✐st ε0, θ ∈ (0, 1) s✉❝❤ t❤❛t ✐❢ ❢♦r ε ∈ (0, ε0) (1 + ε)xn ≥ u ≥ xn − ε ✐♥ B+
1
❚❤❡♥ ✐♥ B+
1/2 ❡✐t❤❡r
xn ≥ u ♦r u ≥ xn − (1 − θ)ε
✶✹ ✴ ✷✵
❍❛r♥❛❝❦✲t②♣❡ ✐♥❡q✉❛❧✐t②
Pr♦♦❢ ❜❛s❡❞ ♦♥
▲❡♠♠❛ ✭❉❡ ❙✐❧✈❛ ✷✵✶✶✮
▲❡t v ❜❡ ❛ ✈✐s❝♦s✐t② s♦❧✉t✐♦♥ ♦❢ t❤❡ ♦♥❡✲♣❤❛s❡ ♣r♦❜❧❡♠ ✐♥ B1✳ ❚❤❡r❡ ❡①✐st ε0, θ ∈ (0, 1) s✉❝❤ t❤❛t ✐❢ ❢♦r a, b ∈ (0, ε0)✱ xn + a ≥ v ≥ xn − b ✐♥ B1 t❤❡♥ ✐♥ B1/2 ❡✐t❤❡r xn + a − θc ≥ v ♦r v ≥ xn − b + θc (c = (a + b)/2)
✶✺ ✴ ✷✵
❈♦♠♣❛❝t♥❡ss
❈♦♥s✐❞❡r ❢♦r εk → 0 ❛ s❡q✉❡♥❝❡ ♦❢ s♦❧✉t✐♦♥s {uk} s❛t✐s❢②✐♥❣ (1 + εk)xn ≥ u ≥ xn − εk ✐♥ B+
1
■♥ t❤❡ ❢♦❧❧♦✇✐♥❣ st❛t❡♠❡♥t wk = xn − uk εk , Gk = {(x, y) ∈ Dk × R : y = wk(x)} ✇❤❡r❡ Dk = (Ω+
k ∪ Fk) ∩ B1/2✳
❈♦r♦❧❧❛r②
❚❤❡r❡ ❡①✐sts w ∈ C(B+
1/2 ∪ B′ 1/2) ❛ s♦❧✉t✐♦♥ ♦❢ t❤❡ ❙✐❣♥♦r✐♥✐
♣r♦❜❧❡♠ s✉❝❤ t❤❛t ❛ s✉❜s❡q✉❡♥❝❡ ❢r♦♠ {Gk} ❝♦♥✈❡r❣❡s t♦ {(x, y) ∈ (B+
1/2 ∪ B′ 1/2) × R : y = w(x)} ✇✐t❤ r❡s♣❡❝t t♦ t❤❡
❍❛✉s❞♦r✛ ❞✐st❛♥❝❡✳
✶✻ ✴ ✷✵
❆❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②
▲❡♠♠❛
- ✐✈❡♥ β ∈ (0, 1/2)✱ t❤❡r❡ ❡①✐st ε0, µ ∈ (0, 1) s✉❝❤ t❤❛t ✐❢ 0 ∈ Λ
❛♥❞ ❢♦r ε ∈ (0, ε0) (1 + ε)xn ≥ u ≥ xn − ε ✐♥ B+
1
t❤❡♥ u ≥ xn − εµ1+β ✐♥ B+
µ
❚❤✐s ✐♠♣❧✐❡s ❛ ♠♦❞✉❧✉s ♦❢ ❝♦♥t✐♥✉✐t② ❢♦r ❛t
✶✼ ✴ ✷✵
❆❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t②
▲❡♠♠❛
- ✐✈❡♥ β ∈ (0, 1/2)✱ t❤❡r❡ ❡①✐st ε0, µ ∈ (0, 1) s✉❝❤ t❤❛t ✐❢ 0 ∈ Λ
❛♥❞ ❢♦r ε ∈ (0, ε0) (1 + ε)xn ≥ u ≥ xn − ε ✐♥ B+
1
t❤❡♥ u ≥ xn − εµ1+β ✐♥ B+
µ
❚❤✐s ✐♠♣❧✐❡s ❛ C1,β ♠♦❞✉❧✉s ♦❢ ❝♦♥t✐♥✉✐t② ❢♦r Γ ❛t 0
✶✼ ✴ ✷✵
❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛
❆ss✉♠❡ 0 ∈ Γ0 ❛♥❞ ❧❡t w = xn − u✳ ❖✉r ❣♦❛❧✱ s❤♦✇✐♥❣ t❤❛t Γ = {xn = w} ∈ C1,1/2(0) ✇✐❧❧ ❢♦❧❧♦✇ ❢r♦♠ H(r) :=
- ∂Br∩Ω+ w2
1/2 ≤ Cr3/2 ■❢ ✇❡ ❝❛♥ ❝❛♣t✉r❡ t❤❡ ❢r❡q✉❡♥❝② ❢r♦♠ ❯s✐♥❣ ❛♥❞ ✐♥t❡❣r❛t✐♦♥ ❜② ♣❛rts
✶✽ ✴ ✷✵
❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛
❆ss✉♠❡ 0 ∈ Γ0 ❛♥❞ ❧❡t w = xn − u✳ ❖✉r ❣♦❛❧✱ s❤♦✇✐♥❣ t❤❛t Γ = {xn = w} ∈ C1,1/2(0) ✇✐❧❧ ❢♦❧❧♦✇ ❢r♦♠ H(r) :=
- ∂Br∩Ω+ w2
1/2 ≤ Cr3/2 ■❢ H(r) = Crk ✇❡ ❝❛♥ ❝❛♣t✉r❡ t❤❡ ❢r❡q✉❡♥❝② k ❢r♦♠ k = N(r) := r d dr ln H(r) = r d
dr
ffl
∂Br∩Ω+ w2
2 ffl
∂Br∩Ω+ w2
❯s✐♥❣ ❛♥❞ ✐♥t❡❣r❛t✐♦♥ ❜② ♣❛rts
✶✽ ✴ ✷✵
❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛
❆ss✉♠❡ 0 ∈ Γ0 ❛♥❞ ❧❡t w = xn − u✳ ❖✉r ❣♦❛❧✱ s❤♦✇✐♥❣ t❤❛t Γ = {xn = w} ∈ C1,1/2(0) ✇✐❧❧ ❢♦❧❧♦✇ ❢r♦♠ H(r) :=
- ∂Br∩Ω+ w2
1/2 ≤ Cr3/2 ■❢ H(r) = Crk ✇❡ ❝❛♥ ❝❛♣t✉r❡ t❤❡ ❢r❡q✉❡♥❝② k ❢r♦♠ k = N(r) := r d dr ln H(r) = r d
dr
ffl
∂Br∩Ω+ w2
2 ffl
∂Br∩Ω+ w2
❯s✐♥❣ ∆w = 0 ❛♥❞ ✐♥t❡❣r❛t✐♦♥ ❜② ♣❛rts d dr
∂Br∩Ω+ w2 = ∂Br∩Ω+ 2wDw · ν + error
= 2r
Br∩Ω+ |Dw|2 + error
✶✽ ✴ ✷✵
❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛
■♥ ❣❡♥❡r❛❧✱ ✐❢ H(r) ≤ Cr3/2 ✐t ♠❛❦❡s s❡♥s❡ t♦ ❡①♣❡❝t lim
r→0+ N(r) =
r d
dr
ffl
∂Br∩Ω+ w2
2 ffl
∂Br∩Ω+ w2
≥ 3/2
▲❡♠♠❛
❚❤❡r❡ ❡①✐st s✉❝❤ t❤❛t ✐s ♥♦♥✲❞❡❝r❡❛s✐♥❣ ✇❤❡r❡ ❍❡r❡ t❤❡ ❛❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t② ✐s ❝r✉❝✐❛❧ ✐♥ ♦r❞❡r t♦ ❥✉st✐❢② t❤❡ ❝♦♠♣✉t❛t✐♦♥s✳
✶✾ ✴ ✷✵
❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛
■♥ ❣❡♥❡r❛❧✱ ✐❢ H(r) ≤ Cr3/2 ✐t ♠❛❦❡s s❡♥s❡ t♦ ❡①♣❡❝t lim
r→0+ N(r) =
r d
dr
ffl
∂Br∩Ω+ w2
2 ffl
∂Br∩Ω+ w2
≥ 3/2
▲❡♠♠❛
❚❤❡r❡ ❡①✐st ε, η > 0 s✉❝❤ t❤❛t (1 + Crε) N(r) ✐s ♥♦♥✲❞❡❝r❡❛s✐♥❣ ✇❤❡r❡
- N(r) = r d
dr ln max( H(r), r3/2+ε)
- H(r) =
ˆ r 2ρ
Bρ∩Ω+ |Dw|2dρ = H(r) + O(r3/2+η)
❍❡r❡ t❤❡ ❛❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t② ✐s ❝r✉❝✐❛❧ ✐♥ ♦r❞❡r t♦ ❥✉st✐❢② t❤❡ ❝♦♠♣✉t❛t✐♦♥s✳
✶✾ ✴ ✷✵
❆❧♠❣r❡♥✲t②♣❡ ♠♦♥♦t♦♥✐❝✐t② ❢♦r♠✉❧❛
■♥ ❣❡♥❡r❛❧✱ ✐❢ H(r) ≤ Cr3/2 ✐t ♠❛❦❡s s❡♥s❡ t♦ ❡①♣❡❝t lim
r→0+ N(r) =
r d
dr
ffl
∂Br∩Ω+ w2
2 ffl
∂Br∩Ω+ w2
≥ 3/2
▲❡♠♠❛
❚❤❡r❡ ❡①✐st ε, η > 0 s✉❝❤ t❤❛t (1 + Crε) N(r) ✐s ♥♦♥✲❞❡❝r❡❛s✐♥❣ ✇❤❡r❡
- N(r) = r d
dr ln max( H(r), r3/2+ε)
- H(r) =
ˆ r 2ρ
Bρ∩Ω+ |Dw|2dρ = H(r) + O(r3/2+η)
❍❡r❡ t❤❡ ❛❧♠♦st ♦♣t✐♠❛❧ r❡❣✉❧❛r✐t② ✐s ❝r✉❝✐❛❧ ✐♥ ♦r❞❡r t♦ ❥✉st✐❢② t❤❡ ❝♦♠♣✉t❛t✐♦♥s✳
✶✾ ✴ ✷✵
❇② ❜❧♦✇✐♥❣✲✉♣ t❤❡ s♦❧✉t✐♦♥ ❛♥❞ ✉s✐♥❣ ♦♥❝❡ ❛❣❛✐♥ ❝♦♥✈❡r❣❡ t♦ t❤❡ ❙✐❣♥♦r✐♥✐ ♣r♦❜❧❡♠ ✇❡ r❡❝♦✈❡r t❤❛t lim
r→0+
N(r) ≥ 3/2 ■♥t❡❣r❛t✐♥❣ ✇❡ r❡❝♦✈❡r t❤❡ ❞❡s✐r❡❞ ❜♦✉♥❞
❚❤❛♥❦s✦
✷✵ ✴ ✷✵
❇② ❜❧♦✇✐♥❣✲✉♣ t❤❡ s♦❧✉t✐♦♥ ❛♥❞ ✉s✐♥❣ ♦♥❝❡ ❛❣❛✐♥ ❝♦♥✈❡r❣❡ t♦ t❤❡ ❙✐❣♥♦r✐♥✐ ♣r♦❜❧❡♠ ✇❡ r❡❝♦✈❡r t❤❛t lim
r→0+
N(r) ≥ 3/2 ■♥t❡❣r❛t✐♥❣ N(r) ∼ r d
dr ln H(r) ✇❡ r❡❝♦✈❡r t❤❡ ❞❡s✐r❡❞ ❜♦✉♥❞
H(r) ≤ Cr3/2
❚❤❛♥❦s✦
✷✵ ✴ ✷✵
❇② ❜❧♦✇✐♥❣✲✉♣ t❤❡ s♦❧✉t✐♦♥ ❛♥❞ ✉s✐♥❣ ♦♥❝❡ ❛❣❛✐♥ ❝♦♥✈❡r❣❡ t♦ t❤❡ ❙✐❣♥♦r✐♥✐ ♣r♦❜❧❡♠ ✇❡ r❡❝♦✈❡r t❤❛t lim
r→0+
N(r) ≥ 3/2 ■♥t❡❣r❛t✐♥❣ N(r) ∼ r d
dr ln H(r) ✇❡ r❡❝♦✈❡r t❤❡ ❞❡s✐r❡❞ ❜♦✉♥❞
H(r) ≤ Cr3/2
❚❤❛♥❦s✦
✷✵ ✴ ✷✵