A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point
A sharp angle inequality is used in a proof of solvability of a general nonlinear elliptic problem with applying of topological methods. Our proof is founded at reducing to the inequality in the case of a domain with a smooth boundary.
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Інститут прикладної математики і механіки НАН України
1999
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Zitieren: | A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point / R.M. Dzhafarov // Нелинейные граничные задачи: сб. науч. тр. — 1999. — Т. 9. — С. 40-45. — Бібліогр.: 2 назв. — англ. |
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irk-123456789-1692702020-06-10T01:26:20Z A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point Dzhafarov, R.M. A sharp angle inequality is used in a proof of solvability of a general nonlinear elliptic problem with applying of topological methods. Our proof is founded at reducing to the inequality in the case of a domain with a smooth boundary. 1999 Article A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point / R.M. Dzhafarov // Нелинейные граничные задачи: сб. науч. тр. — 1999. — Т. 9. — С. 40-45. — Бібліогр.: 2 назв. — англ. 0236-0497 http://dspace.nbuv.gov.ua/handle/123456789/169270 en Нелинейные граничные задачи Інститут прикладної математики і механіки НАН України |
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A sharp angle inequality is used in a proof of solvability of a general nonlinear elliptic problem with applying of topological methods. Our proof is founded at reducing to the inequality in the case of a domain with a smooth boundary. |
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Article |
author |
Dzhafarov, R.M. |
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Dzhafarov, R.M. A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point Нелинейные граничные задачи |
author_facet |
Dzhafarov, R.M. |
author_sort |
Dzhafarov, R.M. |
title |
A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point |
title_short |
A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point |
title_full |
A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point |
title_fullStr |
A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point |
title_full_unstemmed |
A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point |
title_sort |
sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point |
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Інститут прикладної математики і механіки НАН України |
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1999 |
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http://dspace.nbuv.gov.ua/handle/123456789/169270 |
citation_txt |
A sharp angle inequalities for pairs of elliptic operators in the case of domain with a conical point / R.M. Dzhafarov // Нелинейные граничные задачи: сб. науч. тр. — 1999. — Т. 9. — С. 40-45. — Бібліогр.: 2 назв. — англ. |
series |
Нелинейные граничные задачи |
work_keys_str_mv |
AT dzhafarovrm asharpangleinequalitiesforpairsofellipticoperatorsinthecaseofdomainwithaconicalpoint AT dzhafarovrm sharpangleinequalitiesforpairsofellipticoperatorsinthecaseofdomainwithaconicalpoint |
first_indexed |
2025-07-15T04:01:43Z |
last_indexed |
2025-07-15T04:01:43Z |
_version_ |
1837684074988175360 |
fulltext |
A SHARP ANGLE INEQUALITIES FOR PAIRS
OF ELLIPTIC OPERATORS IN THE CASE
OF DOMAIN WITH A CONICAL POINT.
c© R.M. Dzhafarov
A sharp angle inequality is used in a proof of solvability of a general nonlinear elliptic
problem with applying of topological methods. Our proof is founded at reducing to the
inequality in the case of a domain with a smooth boundary [2].
Denotations.
G is a bounded domain with the conical point in the origin of coordinates. ∂G is a
smooth boundary everywhere without of the origin of coordinates.
ρ is a diam G.
Gk = {x ∈ G : ρ
2k+1 ≤ r ≤ ρ
2k , r = |x|}
Ωk is a domain with the smooth boundary wich contain Gk. ℵ0,λ
2m(A,B, Ω) is a class of
linear elliptic with the constant A in Ω operators of order 2m with coefficients bounded
in the norm ‖ · ‖C0,λ(Ω) by B. φk are functions of the unity partition:
∞∑
k=0
φ2
k(x) = 1
∀x ∈ G, supp φk ⊂ Ωk; φk ≤ √
N, x ∈ Gk.
Denote
|Dα(φkrκ)| ≤ const · rκ−|α| (i1)
W l
κ(G) is weighting space with norm
‖u‖W l
κ(G) =
∫
G
∑
|α|≤k
rκ−2(l−|α|)|Dαu|2dx
1
2
◦
W
l
κ(G) is a closure C∞0 (G) in the norm ‖ · ‖W l
κ(G).
Lemma 1. For operators L ∈ ℵ0,λ
2m(A,B, Ωk),
Mk ∈ ℵ0,λ
2m(1, C̃2,Ωk) (where C̃2 is some constant) and functions φk ∈ C∞(Ωk), u ∈
W 2m
κ (G) ∩
◦
W
m
κ (G) following inequality is true
Re
∫
Ωk
rκφ2
k(x)Lu ·Mkudx ≥
≥ Re
∫
Ωk
L(φkur
κ
2 ) ·Mk(φkur
κ
2 )dx−
−C1‖u‖W 2m
κ (Ωk)‖u‖W 2m−1
κ−2 (Ωk) (1)
Lemma 2. Let L ∈ ℵ0,λ
2m(A, B, Ωk). One can designate the constants C̃1, C̃2 and
operator Mk(x,D) ∈ ℵ0,λ
2m(1, C̃2, Ωk) [2] such that ∀u ∈ W 2m
2 (Ωk)∩
◦
W
m
2 (Ω) the relation
Re
∫
Ω
Lu ·Mkudx ≥
≥ C̃1
∫
Ωk
∑
|α|≤2m
( ρ
2k
)2|α|−4m
|Dαu|2dx− C̃2
∫
Ωk
( ρ
2k
)−4m
|u|2dx (2)
is valid.
Lemma 3. If u ∈ W 2m
κ (G) then φkr
κ
2 u ∈ W 2m
2 (G).
Lemma 4. (Interpolating inequality.) For a fixed k and for any function u from
W l
κ(G) the inequality
‖u‖2
W j
κ−2(l−j)(Ωk)
≤ ε1‖u‖2W l
κ(Ωk) + C(ε1)‖u‖2W 0
κ−2l(Ωk), (3)
where j < l, ε1 > 0 is fulfiled.
Those lemmas enable prove a theorem.
Theorem 1. Let L ∈ ℵ0,λ
2m(A,B,G). There exist such constants C2, C3, C̃2 depended
of known parameter A, B, λ, m, G and such operator M =
∞∑
k=0
φ2
k(x)Mk(x,D), Mk ∈
ℵ0,λ
2m(1, C̃2, G) that
∀u ∈
◦
W
m
κ−2m−2l(G) ∩W 2m
κ (G) the inequality
Re
∫
G
rκL(x,D)u ·M(x,D)udx ≥
≥ C2‖u‖2W 2m
κ (G) − C3‖u‖2W 0
κ−4m(G) (4)
is valid.
The lemma 3 enables substitute (2) into (1)
Re
∫
Ω
φ2
k(x)rκLu ·Mkudx ≥
≥ C4
∫
Ωk
∑
|α|≤2m
( ρ
2k
)2|α|−4m
|Dα(φkur
κ
2 |2dx−
−C5
∫
Ωk
( ρ
2k
)
|φkr
κ
2 u|2dx−
−C3‖u‖W 2m−1
κ−2 (Ωk)‖u‖W 2m
κ (Ωk
. (5)
Consider first addend of the right member of (5).
∫
Ωk
∑
|α|≤2m
( ρ
2k
)2|α|−4m
|Dα(φkr
κ
2 )|2dx =
=
∫
Ωk
∑
|α|≤2m
( ρ
2k
)2|α|−4m
|φkr
κ
2 Dαu+
+
∑
β<α; β+γ=α
cβγDβuDγ(φkr
κ
2 )|2dx ≥
≥
∫
Ωk
∑
|α|≤2m
( ρ
2k
)2|α|−4m
|φkr
κ
2 Dαu|2−
− 4
∫
Ωk
∑
|α|≤2m
( ρ
2k
)2|α|−4m
|φkr
κ
2 Dαu|∗
∗|
∑
β<α; β+γ=α
cβγDβuDγ(φkr
κ
2 )|dx ≥
≥ N ·
∫
Gk
∑
|α|≤2m
rκ−2(2m−|α|)|Dαu|2dx−
− ε2
∫
Ωk
∑
|α|≤2m
rκ−2(2m−|α|)|Dαu|2dx−
−C(ε2)
∫
Ωk
∑
|α|≤2m
r2|α|−4m
∑
β<α; β+γ=α
rκ−2γ |Dβu|2dx ≥
≥ N · ‖u‖2W 2m
κ (Gk)−
− ε2 · ‖u‖2W 2m
κ (Ωk)−
−C6
∫
Ωk
∑
|α|≤2m
r2|α|−4m
∑
β<α; β+γ=α
rκ−2α+2β+2α−4m|Dβu|2dx ≥
≥ N · ‖u‖2W 2m
κ (Gk) − ε2 · ‖u‖2W 2m
κ (Ωk) − C7‖u|2W 2m−1
κ−2 (Ωk)
≥
≥ N · ‖u‖2W 2m
κ (Gk) − ε3 · ‖u‖2W 2m
κ (Ωk) − C8‖u|2W 0
κ−4m(Ωk) .
Here Caushy inequality and the interpolating inequality were used. Due to this inequal-
ities we can estimate third addend of the right member of (5) by means of
− ε4‖u‖2W 2m
κ (Ωk) − C9‖u‖2W 0
κ−4m(Ωk).
Now we can write down (5) as
Re
∫
Ωk
φ2
k(x)rκLu ·Mkudx ≥
≥ C10‖u‖2W 2m
κ (Gk) − ε5‖u‖2W 2m
κ (Ωk) − C11‖u‖2W 0
κ−2m(Ωk)
To the left it is possible the substitution Ωk at G. Sum with respect to k and substitute
Ωk at Gk−1 ∩Gk ∩Gk+1 to the right. Thereby we are getting (4).
We introduce ℵl,λ
2m(A,B, G) as a class of a linear elliptic operators with the constant of
ellipticity A and with coefficients having the derivatives of the order d (d ≤ l) bounded
by B ·r−d. Thereto the derivatives of the order l are Holder continuous with the constant
λ and bounded by B · r−l−λ. Let
[u, v]W l
κ(G) =
∫
G
∑
|α|,|β|≤l
cα,β(x)rκ−2l+|α|+|β|DαuDβvdx, (6)
where cαβ(x) are real infinity differentiable functions of following construction
cαβ(x) =
∞∑
k=0
c̃αβ
(
x · 2k
ρ
)
· r−(κ−2l+|α|+|β|)
k =
∞∑
k=0
ck
αβ(x),
where rk = r
ρ/2k . Here c̃αβ are real infinity differentiable functions satisfying to the
conditions
C12‖ũ‖2W l
2(Ω′) ≤
∫
Ω′
∑
|α|,|β|≤l
c̃αβ(x′)DαũDβũdx′ ≤
≤ C13‖ũ‖2W l
2(Ω′),
where Ω′ = 2k
ρ Ωk; c̃αβ have finite support and ∀Ω” ⊂ Rn \ Ω′
∫
Ω”
∑
|α|,|β|≤l
c̃αβ(x′)DαũDβũdx′ ≥ 0.
It can shou that cαβ satisfy to the conditions
C14‖u‖2W l
κ(G) ≤ [u, u]W l
κ(G) ≤ C15‖u‖W l
κ(G).
Lemma 5.
For operators L ∈ ℵl,λ
2m(A,B, Ωk), Mk ∈ ℵl,λ
2m(1, C̃2,Ωk) and functions
φk ∈ C∞(Ωk), u ∈ W 2m+l
κ (Ωk) ∩
◦
W
m
κ−2m−2l(Ωk) the relation
Re[Lu, φ2
kMku]W l
κ(Ωk) ≥≥ Re
∫
Ωk
∑
|α|,|β|≤l
cαβ(x)r|α|+|β|−2lDαL(x,D)(φkr
κ
2 u)∗
∗DβMk(x,D)(φkr
κ
2 u)dx − C16‖u‖W l+2m
κ (Ωk)‖u‖W l+2m−1
κ−2 (Ωk) (7)
is valid.
Lemma 6. Let L ∈ ℵl,λ
2m(A,B, Ωk). There exist such constants C ′1, C
′
2 > 0 and
operator Mk(x, D) ∈ ℵl,λ
2m(1, C ′2, Ωk) that
∀u ∈ W 2m+l
2 (Ωk) ∩
◦
W
m
2 (Ωk) following inequality is fulfiled.
Re
∫
Ωk
∑
|α|,|β|≤l
ck
αβ(x)
( ρ
2k
)|α|+|β|−2l
DαLuDβMkudx ≥
≥ C ′1
∫
Ωk
∑
|α|≤2m+l
( ρ
2k
)2|α|−4m−2l
|Dαu|2dx−
−C ′2
∫
Ωk
( ρ
2k
)−4m−2l
|u|2dx (8)
Theorem 2. Let L ∈ ℵl,λ
2m(A,B, G). There exist such real infinity differentiable func-
tions cαβ (|α|, |β| ≤ l) satisfying to the condition
C14‖u‖2W l
κ(G) ≤ [u, u]W l
κ(G) ≤ C15‖u‖2W l
κ(G),
the positive constants K1, K2, C ′2 depending of known parameter only and such operator
M =
∑∞
k=0 φ2
k(x)Mk(x, D), Mk(x,D) ∈ ℵl,λ
2m(1, C ′2, G) that for any function u ∈
W 2m+l
κ (G) ∩
◦
W
m
κ−2m−2l(G) the inequality
Re[Lu,Mu]W l
κ(G) ≥ K1‖u‖2W 2m+l
κ (G)
− K2‖u‖2W 0
κ−4m−2l(G) (9)
is valid.
On the lemma 3 φkr
κ
2 u ∈ W 2m+l
κ (G). Therefore
Re[Lu, φ2
kMku]W l
κ(G) ≥
≥ C17
∫
Ωk
∑
|α|≤2m+l
( ρ
2k
)2|α|−4m−2l
|Dα(φkr
κ
2 u)|2dx−
−C18
∫
Ωk
( ρ
2k
)−4m−2l
|φkr
κ
2 u|2dx−
−C19‖u‖W 2m+l
κ (Ωk)‖u‖W 2m+l−1
κ−2 (Ωk) (10)
Consider the first addend of the right member of (10). We shall be use interpolating
inequality and inequality |a + b| ≥ |a|2 − 4|a| · |b|.
∫
Ωk
∑
|α|≤2m+l
( ρ
2k
)2|α|−4m−2l
|Dα(φkr
κ
2 u)|2dx =
=
∫
Ωk
∑
|α|≤2m+l
( ρ
2k
)2|α|−4m−2l
|φkr
κ
2 Dαu−
−
∑
γ<α; γ+δ=α
cγδD
δ(φkr
κ
2 )Dγu|2dx ≥
≥ N · C20
∫
Gk
∑
|α|≤2m+l
rκ−2(2m+l−|α|)|Dαu|2dx−
−C21
∫
Ωk
∑
|α|≤2m+l
r2|α|−4m−2l
∑
γ<α; γ+δ=α
{
r
κ
2−|α|+|γ||Dγu|
}
∗
∗{
r
κ
2 |Dαu|} dx ≥
≥ N · C20‖u‖2W 2m+l
κ (Gk)
−
− ε6‖u‖2W 2m+l
κ (Ωk)
− C22‖u‖2W 2m+l−1
κ−2 (Ωk)
≥ N · C20‖u‖2W 2m+l
κ (Gk)
−
− ε7‖u‖2W 2m+l
κ (Ωk)
−
−C23‖u‖2W 0
κ−4m−2l(Ωk) (11)
We apply Caushy inequality and inequality (3) to third addend of the right member of
(10). Thereby we get
Re[Lu, φ2
kMku]W l
κ(Ωk) ≥
≥ N · C20‖u‖2W 2m+l
κ (Gk)
− ε8‖u‖2W 2m+l
κ (Ωk)
− C24‖u‖2W 0
κ−4m−2l(Ωk) (12)
from (10). In the left member we substitute Ωk at G and in the right member substitute
Ωk at Gk−1 ∪Gk ∪Gk+1. Summing with respect to k gives (9).
References
1. Kondrat’ev V.A., Boundary value problems for elliptic equations in domains with conical or angular
points, Trudy Moskovskogo Mat. Obschestva 16 (1967), 219-292.
2. Skrypnik I.V., Nonlinear elliptic boundary value problems, Leipzig: B.G. Teubner Verlagsges, 1986.
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