Displaying similar documents to “Bifurcation theorems for nonlinear problems with lack of compactness”

On bifurcation and uniqueness results for some semilinear elliptic equations involving a singular potential

Manuela Chaves, Jesús García-Azorero (2006)

Journal of the European Mathematical Society

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We present some results concerning the problem Δ u = λ u | x | 2 + u q , u > 0 in Ω , u | Ω = 0 , where 0 < q < ( N + 2 ) / ( N 2 ) , q 1 , λ 0 and Ω is a smooth bounded domain containing the origin. In particular, bifurcation and uniqueness results are discussed.

The supports of higher bifurcation currents

Romain Dujardin (2013)

Annales de la faculté des sciences de Toulouse Mathématiques

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Let ( f λ ) λ Λ be a holomorphic family of rational mappings of degree d on 1 ( ) , with k marked critical points c 1 , ... , c k . To this data is associated a closed positive current T 1 T k of bidegree ( k , k ) on Λ , aiming to describe the simultaneous bifurcations of the marked critical points. In this note we show that the support of this current is accumulated by parameters at which c 1 , ... , c k eventually fall on repelling cycles. Together with results of Buff, Epstein and Gauthier, this leads to a complete characterization of Supp ( T 1 T k ) . ...

A bifurcation theory for some nonlinear elliptic equations

Biagio Ricceri (2003)

Colloquium Mathematicae

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We deal with the problem ⎧ -Δu = f(x,u) + λg(x,u), in Ω, ⎨ ( P λ ) ⎩ u Ω = 0 where Ω ⊂ ℝⁿ is a bounded domain, λ ∈ ℝ, and f,g: Ω×ℝ → ℝ are two Carathéodory functions with f(x,0) = g(x,0) = 0. Under suitable assumptions, we prove that there exists λ* > 0 such that, for each λ ∈ (0,λ*), problem ( P λ ) admits a non-zero, non-negative strong solution u λ p 2 W 2 , p ( Ω ) such that l i m λ 0 | | u λ | | W 2 , p ( Ω ) = 0 for all p ≥ 2. Moreover, the function λ I λ ( u λ ) is negative and decreasing in ]0,λ*[, where I λ is the energy functional related to ( P λ ). ...

Strong bifurcation loci of full Hausdorff dimension

Thomas Gauthier (2012)

Annales scientifiques de l'École Normale Supérieure

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In the moduli space d of degree  d rational maps, the bifurcation locus is the support of a closed ( 1 , 1 ) positive current T bif which is called the bifurcation current. This current gives rise to a measure μ bif : = ( T bif ) 2 d - 2 whose support is the seat of strong bifurcations. Our main result says that supp ( μ bif ) has maximal Hausdorff dimension 2 ( 2 d - 2 ) . As a consequence, the set of degree  d rational maps having ( 2 d - 2 ) distinct neutral cycles is dense in a set of full Hausdorff dimension.

S -shaped component of nodal solutions for problem involving one-dimension mean curvature operator

Ruyun Ma, Zhiqian He, Xiaoxiao Su (2023)

Czechoslovak Mathematical Journal

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Let E = { u C 1 [ 0 , 1 ] : u ( 0 ) = u ( 1 ) = 0 } . Let S k ν with ν = { + , - } denote the set of functions u E which have exactly k - 1 interior nodal zeros in (0, 1) and ν u be positive near 0 . We show the existence of S -shaped connected component of S k ν -solutions of the problem u ' 1 - u ' 2 ' + λ a ( x ) f ( u ) = 0 , x ( 0 , 1 ) , u ( 0 ) = u ( 1 ) = 0 , where λ > 0 is a parameter, a C ( [ 0 , 1 ] , ( 0 , ) ) . We determine the intervals of parameter λ in which the above problem has one, two or three S k ν -solutions. The proofs of the main results are based upon the bifurcation technique.

On butterfly-points in β X , Tychonoff products and weak Lindelöf numbers

Sergei Logunov (2022)

Commentationes Mathematicae Universitatis Carolinae

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Let X be the Tychonoff product α < τ X α of τ -many Tychonoff non-single point spaces X α . Let p X * be a point in the closure of some G X whose weak Lindelöf number is strictly less than the cofinality of τ . Then we show that β X { p } is not normal. Under some additional assumptions, p is a butterfly-point in β X . In particular, this is true if either X = ω τ or X = R τ and τ is infinite and not countably cofinal.

The bicrossed products of H 4 and H 8

Daowei Lu, Yan Ning, Dingguo Wang (2020)

Czechoslovak Mathematical Journal

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Let H 4 and H 8 be the Sweedler’s and Kac-Paljutkin Hopf algebras, respectively. We prove that any Hopf algebra which factorizes through H 8 and H 4 (equivalently, any bicrossed product between the Hopf algebras H 8 and H 4 ) must be isomorphic to one of the following four Hopf algebras: H 8 H 4 , H 32 , 1 , H 32 , 2 , H 32 , 3 . The set of all matched pairs ( H 8 , H 4 , , ) is explicitly described, and then the associated bicrossed product is given by generators and relations.

The subspace of weak P -points of *

Salvador García-Ferreira, Y. F. Ortiz-Castillo (2015)

Commentationes Mathematicae Universitatis Carolinae

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Let W be the subspace of * consisting of all weak P -points. It is not hard to see that W is a pseudocompact space. In this paper we shall prove that this space has stronger pseudocompact properties. Indeed, it is shown that W is a p -pseudocompact space for all p * .

On a Kirchhoff-Carrier equation with nonlinear terms containing a finite number of unknown values

Nguyen Vu Dzung, Le Thi Phuong Ngoc, Nguyen Huu Nhan, Nguyen Thanh Long (2024)

Mathematica Bohemica

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We consider problem (P) of Kirchhoff-Carrier type with nonlinear terms containing a finite number of unknown values u ( η 1 , t ) , , u ( η q , t ) with 0 η 1 < η 2 < < η q < 1 . By applying the linearization method together with the Faedo-Galerkin method and the weak compact method, we first prove the existence and uniqueness of a local weak solution of problem (P). Next, we consider a specific case ( P q ) of (P) in which the nonlinear term contains the sum S q [ u 2 ] ( t ) = q - 1 i = 1 q u 2 ( ( i - 1 ) q , t ) . Under suitable conditions, we prove that the solution of ( P q ) converges to the solution...

A compactness result for polyharmonic maps in the critical dimension

Shenzhou Zheng (2016)

Czechoslovak Mathematical Journal

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For n = 2 m 4 , let Ω n be a bounded smooth domain and 𝒩 L a compact smooth Riemannian manifold without boundary. Suppose that { u k } W m , 2 ( Ω , 𝒩 ) is a sequence of weak solutions in the critical dimension to the perturbed m -polyharmonic maps d d t | t = 0 E m ( Π ( u + t ξ ) ) = 0 with Φ k 0 in ( W m , 2 ( Ω , 𝒩 ) ) * and u k u weakly in W m , 2 ( Ω , 𝒩 ) . Then u is an m -polyharmonic map. In particular, the space of m -polyharmonic maps is sequentially compact for the weak- W m , 2 topology.