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Stability of resonances for the Dirac operator 狄拉克算子共振的稳定性
IF 0.8 4区 数学 Q3 Mathematics Pub Date : 2024-01-26 DOI: 10.1090/spmj/1788
D. Mokeev

The Dirac operator on the semi-axis with a compactly supported potential is investigated. Let ( k n ) n 1 (k_n)_{ngeq 1} be the sequence of its resonances, taken with multiplicities and ordered so that | k n | |k_n| do not decrease as n n grows. It is proved that for any sequence ( r n ) n 1 1 (r_n)_{ngeq 1} in ell ^1 such that the points k n + r n k_n + r_n remain in the lower half-plane for all

本文研究了半轴上具有紧凑支撑势的狄拉克算子。设 ( k n ) n ≥ 1 (k_n)_{ngeq 1} 为其共振序列,取其乘数并排序,使得| k n | |k_n| 不随 n n 的增长而减小。实验证明,对于任意序列 ( r n ) n ≥ 1 ∈ 1 ℓ 1 (r_n)_{ngeq 1}in ell ^1,使得点 k n + r n k_n + r_n 对于所有 n ≥ 1 ngeq 1 都保持在下半平面,序列 ( k n + r n ) n ≥ 1 (k_n + r_n)_{ngeq 1} 也是类似算子的共振序列。此外,研究还表明,在这种扰动下,狄拉克算子的势会连续变化。
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引用次数: 0
Representation of analytic functions in bounded convex domains on the complex plane 复平面上有界凸域解析函数的表示
4区 数学 Q3 Mathematics Pub Date : 2023-11-09 DOI: 10.1090/spmj/1779
A. Krivosheev, A. Rafikov
The paper is devoted to entire functions of exponential type and regular growth. Exceptional sets are investigated outside of which these functions have estimates from below that asymptotically coincide with their estimates from above. An explicit construction of an exceptional set, which consists of disks with centers at zeros of the entire function, is indicated. The concept of a properly balanced set is introduced, which is a natural generalization of the concept of a regular set by B. Ya. Levin. It is proved that the zero set of an entire function is properly balanced if and only if each function analytic in the interior of the conjugate diagram of the entire function in question and continuous up to the boundary is represented by a series of exponential monomials whose exponents are zeros of this entire function. This result generalizes the classical result of A. F. Leont′ev on the representation of analytic functions in a convex domain to the case of a multiple zero set.
本文主要研究指数型整函数和正则增长函数。研究了异常集,在异常集之外,这些函数的估计从下面渐近地与它们的估计从上面重合。给出了一个异常集的显式构造,该异常集由以整个函数零点为中心的圆盘组成。引入了适当平衡集的概念,它是B. Ya对正则集概念的自然推广。莱文。证明了一个完整函数的零集是适当平衡的,当且仅当在整个函数的共轭图内部解析且连续到边界的每个函数都用指数为该完整函数的零的指数单项式表示。这一结果推广了a . F. Leont 'ev关于解析函数在凸域上表示的经典结果到多重零集的情况。
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引用次数: 0
On finite algebras with probability limit laws 关于具有概率极限律的有限代数
4区 数学 Q3 Mathematics Pub Date : 2023-11-09 DOI: 10.1090/spmj/1782
A. Yashunsky
An algebraic system has a probability limit law if the values of terms with independent identically distributed random variables have probability distributions that tend to a certain limit (the limit law) as the number of variables in a term grows. For algebraic systems on finite sets, it is shown that, under some geometric conditions on the set of term value distributions, the existence of a limit law strongly restricts the set of possible operations in the algebraic system. In particular, a system that has a limit law without zero components necessarily consists of quasigroup operations (with arbitrary arity), while the limit law is necessarily uniform. Sufficient conditions are also proved for a system to have a probability limit law, which partly match the necessary ones.
如果具有独立同分布随机变量的项的值具有随着项中变量数量的增加而趋向于某个极限(极限定律)的概率分布,则代数系统具有概率极限定律。对于有限集合上的代数系统,在项值分布集合上的某些几何条件下,极限律的存在性强烈地约束了代数系统中可能操作集合的存在性。特别地,具有无零分量的极限律的系统必然由准群运算(具有任意性)组成,而极限律必然是一致的。并证明了系统具有概率极限律的充分条件,该充分条件与必要条件部分匹配。
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引用次数: 1
Sufficient conditions for the minimality of biconcave functions 双凹函数极小性的充分条件
4区 数学 Q3 Mathematics Pub Date : 2023-11-09 DOI: 10.1090/spmj/1781
M. Novikov
This paper describes sufficient conditions under which a biconcave function B : S = { ( x , y ) R 2 : x 2 y x + 2 } R mathcal {B}colon mathfrak {S}={ (x,y)in mathbb {R}^2colon x-2le yle x+2 }to mathbb {R} is minimal with respect to an obstacle L : S [ , + ) Lcolon mathfrak {S}to [-infty ,+infty ) , that is, it is the pointwise minimal among all biconcave functions B : S
本文给出了双凹函数B: S =的充分条件 { (x, y)∈r2: x−2≤y≤x + 2 } →r mathcal {b}colon mathfrak {s}={(x,y)in mathbb {r}^2colon x-2le yle X +2}to mathbb {r} S→[−∞,+∞)Lcolon mathfrak {s}to [-]infty ,+infty ),即它是所有双凹函数B: S→R B中的点极小值colon mathfrak {s}to mathbb {r} 满足不等式B≥L Bge L。
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引用次数: 1
Torsion divisors of plane curves and Zariski pairs 平面曲线和Zariski对的扭转因子
4区 数学 Q3 Mathematics Pub Date : 2023-11-09 DOI: 10.1090/spmj/1776
E. Artal Bartolo, Sh. Bannai, T. Shirane, H. Tokunaga
This paper is devoted to the study of the embedded topology of reducible plane curves having a smooth irreducible component. In previous studies, the relationship between the topology and certain torsion classes in the Picard group of degree zero of the smooth component was implicitly considered. Here this relationship is formulated clearly and a criterion is given for distinguishing the embedded topology in terms of torsion classes. Furthermore, a method is presented for systematically constructing examples of curves where this criterion is applicable, and new examples of Zariski N N -tuples are produced.
本文研究了具有光滑不可约分量的可约平面曲线的嵌入拓扑。在以往的研究中,隐式地考虑了光滑分量的零度Picard群中某些扭转类与拓扑之间的关系。本文对这种关系进行了明确的表述,并给出了从扭转类的角度来区分嵌入拓扑的判据。在此基础上,提出了一种系统构造适用于该准则的曲线实例的方法,并给出了Zariski N N元组的新实例。
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引用次数: 0
Derivative of the Minkowski function for numbers with bounded partial quotients 部分商有界数的Minkowski函数的导数
4区 数学 Q3 Mathematics Pub Date : 2023-11-09 DOI: 10.1090/spmj/1777
D. Gayfulin
It is well known that the derivative of the Minkowski function ? ( x ) ?(x) (whenever exists) may take only two values: 0 0 and + +infty . Let E n textbf {E}_n be the set of irrational numbers on the interval [ 0 ; 1 ] [0; 1] whose partial quotients (related to the continued fraction expansion) do not exceed n n . It is also known that the quantity ? ( x ) ?’(x) at a point
众所周知,闵可夫斯基函数的导数?(x) ?(x)(无论何时存在)只能取两个值:0 0和+∞+ infty。设textbfen E_n{为区间[0;1] [0;1]其部分商(与连分式展开有关)不超过n n。还知道数量是多少?' (x) ? ' (x)在点x = [0;A 1, A 2,…,A t,…]x=[0;a_1,a_2, }dots,a_t, dots]与算术平均值的极限行为(A 1+ A 2+⋯+ A t)/t (a_1+a_2+ dots +a_t)/t有关。特别是a . Dushistova, I. Kan和n . Moshchevitin证明,如果x∈E n x intextbfE_n{满足1 + a 2 +⋯+ at &gt;(κ 1 (n)−ε) t a_1+a_2+ }dots +a_t&gt;(kappa ^(n{)_1}- varepsilon) t,其中ε &gt;0 varepsilon &gt;0和κ 1 (n) kappa ^(n{)_1}是某个显式常数,则?' (x)=+∞? ' (x)=+ infty。他们还发现,κ 1 (n) kappa ^(n{)_1}的数量不能增加。本文研究了一个对偶问题:a 1+a 2+⋯+a t−κ 1 (n) t a_1+a_2+ dots +a_t- kappa ^(n{)_1} t有多小?' (x)=0 ? ' (x)=0 ?找到了该问题的最优估计。
{"title":"Derivative of the Minkowski function for numbers with bounded partial quotients","authors":"D. Gayfulin","doi":"10.1090/spmj/1777","DOIUrl":"https://doi.org/10.1090/spmj/1777","url":null,"abstract":"It is well known that the derivative of the Minkowski function <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"question-mark left-parenthesis x right-parenthesis\"> <mml:semantics> <mml:mrow> <mml:mo>?</mml:mo> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">?(x)</mml:annotation> </mml:semantics> </mml:math> </inline-formula> (whenever exists) may take only two values: <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"0\"> <mml:semantics> <mml:mn>0</mml:mn> <mml:annotation encoding=\"application/x-tex\">0</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"plus normal infinity\"> <mml:semantics> <mml:mrow> <mml:mo>+</mml:mo> <mml:mi mathvariant=\"normal\">∞<!-- ∞ --></mml:mi> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">+infty</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. Let <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"bold upper E Subscript n\"> <mml:semantics> <mml:msub> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mtext mathvariant=\"bold\">E</mml:mtext> </mml:mrow> <mml:mi>n</mml:mi> </mml:msub> <mml:annotation encoding=\"application/x-tex\">textbf {E}_n</mml:annotation> </mml:semantics> </mml:math> </inline-formula> be the set of irrational numbers on the interval <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"left-bracket 0 semicolon 1 right-bracket\"> <mml:semantics> <mml:mrow> <mml:mo stretchy=\"false\">[</mml:mo> <mml:mn>0</mml:mn> <mml:mo>;</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\"false\">]</mml:mo> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">[0; 1]</mml:annotation> </mml:semantics> </mml:math> </inline-formula> whose partial quotients (related to the continued fraction expansion) do not exceed <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"n\"> <mml:semantics> <mml:mi>n</mml:mi> <mml:annotation encoding=\"application/x-tex\">n</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. It is also known that the quantity <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"question-mark Superscript prime Baseline left-parenthesis x right-parenthesis\"> <mml:semantics> <mml:mrow> <mml:msup> <mml:mo>?</mml:mo> <mml:mo>′</mml:mo> </mml:msup> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">?’(x)</mml:annotation> </mml:semantics> </mml:math> </inline-formula> at a point <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:","PeriodicalId":51162,"journal":{"name":"St Petersburg Mathematical Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135241092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Cauchy problem for the nonlinear Hirota equation in the class of periodic infinite-zone functions 周期无穷区函数中非线性Hirota方程的Cauchy问题
4区 数学 Q3 Mathematics Pub Date : 2023-11-09 DOI: 10.1090/spmj/1780
G. Mannonov, A. Khasanov
In this paper, the method of inverse spectral problem is used to integrate the nonlinear Hirota equation in the class of periodic infinite-zone functions. An evolution of the spectral data of the periodic Dirac operator is introduced, where the coefficient of this operator is the solution of the nonlinear Hirota equation. The solvability of the Cauchy problem for an infinite system of Dubrovin differential equations in the class of five times continuously differentiable periodic infinite-zone functions is shown. In addition, it is proved that if the initial function is a π pi -periodic real-analytic function, then the solution of the Cauchy problem for the Hirota equation is also a real-analytic function in the variable x x ; and if the number π / 2 pi /2 is a period (antiperiod) of the initial function, then the number π / 2 pi /2 is a period (antiperiod) in the variable x x of the solution of the Cauchy problems for the Hirota equation.
本文利用谱逆问题的方法对一类周期无穷区函数中的非线性Hirota方程进行积分。介绍了周期狄拉克算子谱数据的演化,其中该算子的系数是非线性Hirota方程的解。给出了一类五次连续可微周期无穷带函数的Dubrovin微分方程无穷系的Cauchy问题的可解性。此外,证明了如果初始函数是π π -周期实解析函数,则Hirota方程的Cauchy问题的解也是变量x x上的实解析函数;如果数π /2 pi /2是初始函数的一个周期(反周期),那么数π /2 pi /2就是变量x x的一个周期(反周期),这是Hirota方程的柯西问题的解。
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引用次数: 0
On the electric impedance tomography problem for nonorientable surfaces with internal holes 内孔不可定向表面的电阻抗层析问题
4区 数学 Q3 Mathematics Pub Date : 2023-11-09 DOI: 10.1090/spmj/1778
D. Korikov
Let ( M , g ) (M,g) be a compact (in general, nonorientable) surface with boundary M partial M and let Γ 0 Gamma _0 , …, Γ m 1 Gamma _{m-1} be connected components of M partial M . Let u = u f ( x ) u=u^{f}(x) be a solution to the problem Δ
设(M,g) (M,g)是一个边界为∂M的紧曲面(一般来说,是不可定向的) partial M,设Γ 0 Gamma _0,…,Γ m−1 Gamma _{m-1} 是∂M的连通分量 partial M。令u=u f (x) u=u^{f}(x)是问题的解Δ g u = 0 Delta _{g}u=0 in M M, u | Γ 0 = f ubig |_{Gamma _0}=f, u | Γ j = 0 ubig |_{Gamma _j}=0, j=1 j=1,…,m ' m ',∂ν u | Γ j= 0 partial _{nu }你big |_{Gamma _j}=0, j=m ' +1 j=m ' +1,…,m−1 m-1,其中ν nu 是外法线。对于这个问题,可以将DN映射Λ: f∈∂ν u f | Γ 0联系起来 Lambda colon fmapsto partial _{nu }u^{f}big |_{Gamma _0} . 目的是从Λ中确定M Lambda . 为此,应用了边界控制方法的代数版本。关键的工具是代数A mathfrak {a} 在M M的适当可定向双盖上的函数全纯。证明了A mathfrak {a} 由Λ决定 Lambda 直到等距同构。代数A的谱 mathfrak {a} 提供M ' M ' M的相关副本。此副本的保角等效于M M,而其DN映射与Λ一致 Lambda .
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引用次数: 0
Improved resolvent 𝐿²-approximations in homogenization of fourth order operators 改进的求解方法𝐿²-四阶算子均匀化的近似
IF 0.8 4区 数学 Q3 Mathematics Pub Date : 2023-07-26 DOI: 10.1090/spmj/1772
S. Pastukhova

A divergent elliptic operator A ε A_varepsilon of the fourth order with ε varepsilon -periodic coefficients acting in the space R d mathbb {R}^d is treated, where ε varepsilon is a small parameter. For the resolvent ( A ε + 1 ) 1 (A_varepsilon +1)^{-1} , approximations are constructed in the operator ( L 2 L 2 )

研究了一个具有ε varepsilon周期系数的四阶发散椭圆算子A ε A_varepsilon作用于空间rd mathbb {R}^d,其中ε varepsilon是一个小参数。对于解(A ε +1)−1 (A_varepsilon +1)^{-1},在算子(l2→l2) {(L^2到L^2)} -范数中构造了近似,余数为ε 3 varepsilon ^3阶。采用了双尺度展开式平滑法。
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引用次数: 2
Hölder classes in the 𝐿^{𝑝} norm on a chord-arc curve in ℝ³ 在一个弦弧曲线上的𝐿^{𝑝}范数中的Hölder类
IF 0.8 4区 数学 Q3 Mathematics Pub Date : 2023-07-26 DOI: 10.1090/spmj/1769
T. Alexeeva, N. Shirokov

The Hölder classes L p α ( L ) L_p^{alpha } (L) in the L p ( L ) L_p(L) norm on a chord-arc curve L L in R 3 mathbb {R}^3 are defined and direct and inverse approximation theorems are proved for functions from these classes by functions harmonic in a neighborhood of the curve. The approximation is estimated in the L p ( L ) L^p(L) norm, the direct theorem is proved for a certain subclass of

定义了弦弧曲线L L中的L p(L) L_p(L)范数L L在R 3 mathbb {R}^3中的Hölder类L p α (L) L_p^{alpha} (L),并利用曲线邻域中的调和函数证明了这些类函数的正逼近定理和逆逼近定理。在L p(L) L^p(L)范数中估计了近似,证明了L p α (L) L^ α _p(L)的某个子类的正定理,逆定理涵盖了整个Hölder类。
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引用次数: 1
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St Petersburg Mathematical Journal
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