Tchebyshev Approximation by S01(Δ)over Some Special Triangulations

The critical point set plays a central role in the theory of Tchebyshev approximation.Generally,in multivariate Tchebyshev approximation,it is not a trivial task to determine whether a set is critical ...     

Tchebyshev Approximation by S01（△） over Some Special Triangulations

The critical point set plays a central role in the theory of Tchebyshev approximation.Generally,in multivariate Tchebyshev approximation,it is not a trivial task to determine whether a set is critical or not.In this paper,we study the characterization of the critical point set of S 0 1(△) in geometry,where is restricted to some special triangulations(bitriangular,single road and star triangulations).Such geometrical characterization is convenient to use in the determination of a critical point set.     

On Converse Theorem of Best Approximation by Polynomials in Bergman Spaces H_q~p(p>0,q>1)

A Bernstein type theorem and a converse theorem of best approximation by polynomials inBergman spaces H_q~p(p>0,q>1) are proved.Some proofs and results in [1] are in proved.     

关于一类S~（1，1）_3（△~（2）_（mn））插值与逼近

设△￣（２）＿（ｍｘ）是矩形域Ｄ＝［ａ，ｂ］［ｃ，ｄ］的Ⅱ－型三角剖分．Ｓ￣（１，１）＿３（△￣（２）＿（ｍｘ）是带边界条件的三元三次样条空间：本文我们将讨论一类Ｓ￣（１，１）＿３（△￣（２）＿（ｍｘ））的插值问题，证明了它的存在性，唯一性及逼近阶：如果ｆ∈Ｃ￣４（Ｄ），则有｜ｆ－ｓ｜≤ｋ（ｌ）．ｍａｘ（ρ△，ρ￣（－１）＿△）．‖ｆ‖．．ｈ￣２．     

(l~(β_1))_(β_2)~*的次表示定理与l~(β_1)的非局部β_2-凸性(0＜β_1＜β_2≤1)(英文)

对0<β_1<β_2≤1,本文得到l~(β_1)的β_2-共轭锥的次表示定理(l~(β_1))_(β_2)~*■m~+×m~+,证明l~(β_1)不是局部β_2-凸空间.     

关于公式[t~m]=∫_0~(+∞)t~me~(-st)dt=(Γ(m+1))/(S~(m+1)[常数m>-1,R_e(s)>0]的一个简单证明

<正> [说明]对此公式的证明,大多数有关的教学参考书,如南京工学院数学教研组编(以下简称南工编)《积分变换》(第一版)[美]C.RAYWYLIE著,西安交通大学教学系《工程数学》翻译组译《高等工程数学》;西南交通大学黄克欧等编《高等工程数学》等,都处理得过于简略,因而缺乏数学上的严密性。南工编《积分变换》(第二版)对此作了修改,给出了严格的数学证明但又失之过繁。本文对此公式给出了较为简单的证明。     

奇数维spin~c流形和S~1作用(英文)

本文研究了奇数维spin~c流形上的等边指标定理.用这些指标定理和一些复分析的讨论,得到了两个奇数维spin~c流形上的Atiyah-Hirzebruch类型消灭定理,结果推广了刘-王的消灭定理.     

S_2~1(△_(mn)~((2)))上的整节点插值

[1]中提出一种二元样条的插值方法,后来[2]对此种方法进行了较深入的分析.[2]中区分了二种不同类型的插值点:基本插值点和附加插值点;也给出了两种不同类型的插值:整节点插值和半整节点插值。本文研究空间S_2~1(△_(mn)~((2)))上的整节点插值,讨论插值     

ON INTERPOLATION BY S_2~1(△_(m,n)~((2)))

Let △_(m,n)~(2)be a subdivision of D:[a,b]×[c,d](Fig.1),_1arelengths of[a,b]and[c,d]respectively,and h_1=_1/m,h_2=_2/n.     

Approximation of the Bessel function Jν(x) by numerical integration

An approximation is given for the Bessel function J_ν(x), with real ν, based on the application of a quasi-gaussian (i.e. gaussian with preassigned nodes in ?1 and +1) quadrature formula to the integral representation

$\text{J}{}_{\mathrm{\nu }}\text{(x)=}\text{(}\text{x}\text{2}\text{)}{}^{\mathrm{\nu }}\text{π}\text{Φ(ν+}\text{1}\text{2}\text{)}\text{∫}\text{?1}\text{1}\text{(1?t}{}^2\text{)ν?}\text{1}\text{2}\text{cos xt dt}$

In the case of integer values of ν, we compare our results with the approximation obtained by applying the trapezoidal rule to the representation

$\text{J}{}_{\mathrm{<mtext>n</mtext>}}\text{(x)=}\text{1}\text{π}\text{∫}\text{0}\text{π}\text{cos}\text{(}\text{x sin}\text{θ ?}\text{n}\text{θ)}\text{d}\text{θ}$

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勿忘(0)~(1/2)=0

我们知道 0 =0 ,但在解题过程中 ,却常常忽视了 ,这反映了我们考虑问题的片面性 .例 1　当α、β取什么范围内的值时 ,式子sin2αcosβ有意义 ?错解　由 sin2 α≥ 0知　 sin2 αcosβ≥ 0等价于 cosβ≥ 0 .即β∈ [2 kπ - π2 ,2 kπ π2 ](k∈ Z) .分析　因为学生牢记“实数的平方为非负数”,即α∈ R时 ,sin2 α≥ 0 .所以由sin2 αcosβ≥ 0推导出 cosβ≥ 0 .事实上 ,这漏掉了另一种情况 :sinα =0 ,cosβ∈ R时原式也有意义 .即α =kπ,且β∈ R,k∈ Z.正解　原式有意义等价于 cosβ≥ 0或sinα =0 .解得β∈ [2 kπ - π2 ,2 k…     

On Some Total Chromatic Number ofOuterplanar Graphs with △(G) =6

ＯｎＳｏｍｅＴｏｔａｌＣｈｒｏｍａｔｉｃＮｕｍｂｅｒｏｆＯｕｔｅｒｐｌａｎａｒＧｒａｐｈｓｗｉｔｈ△（Ｇ）＝６￥ＺｈａｎｇＺｈｏｎｇｆｕ；ＬｕＸｉｎｚｈｏｎｇ；ＨａｎＪｉｎｃａｎｇ；ＬｉｎＫｅｒｏｎｇ（ＬａｎｚｈｏｕＲａｉｌｗａｙＩｎｓｔｉｔｕｔｅ，...     

On representations of GL(n) distinguished by GL(n − 1) over a p-adic field

For a nonarchimedean local field F, let GL(n):= GL(n, F) and GL(n?1) be embedded in GL(n) via g ? ( _{0 1} ^{g 0} ). Let π be an irreducible admissible representation of GL(n) for n ≥ 3. We prove that π is GL(n ? 1)-distinguished if and only if the Langlands parameter L(π) associated to π by the Local Langlands Correspondence has a subrepresentation L(11 _n?2) of dimension n?2 corresponding to the trivial representation of GL(n?2) such that the two-dimensional quotient L(π)/L(11 _n?2) corresponds either to an infinite-dimensional representation or the one-dimensional representations $\nu ^{ \pm (\tfrac{{n - 2}}{2})} $ of GL(2). We also prove that, for a parabolic subgroup P of GL(n) and an irreducible admissible representation ρ of the Levi subgroup of P, $\dim _\mathbb{C} (Hom_{GL(n - 1)} [ind_P^{GL(n)} (\rho ),\mathbb{I}_{n - 1} ]) \leqslant 2$ . For the standard Borel subgroup B _n of GL(n) and characters x _i of GL(1), we classify all representations ξ of the form $ind_{B_n }^{GL(n)} (\chi _1 \otimes \cdots \otimes \chi _n )$ for which $\dim _\mathbb{C} (Hom_{GL(n - 1)} [\xi ,\mathbb{I}_{n - 1} ]) = 2$ .     

S~1上一类自映射的迭代根(英文)

本文给出了圆周上dege(f)=0的分段严格单调的连续映射f存在任意阶迭代根的充分必要条件,得出了f存在任意阶迭代根等价于可以嵌入一个拟半流的结论.     

球面S~(d-1)上的广义Ul'yanov型不等式

本文对于单位球面上的经典连续模,给出了一个非常有用的广义Ul'yanov型不等式.该不等式在球面多项式逼近、球面嵌入理论以及球面上函数空间的插值理论等领域有着非常重要的应用.我们的证明基于球面调和多项式展开的新的估计,这些估计本身也具有独立的意义.     

THE HOPF BIFURCATION OF QUADRATIC SYSTEM (I)_(n=0)

δlm is the parameter space of quadratic system (I)n=0. A partition of parameters corresponding to the existence and nonexistence of the limit cycle of the system is given in detail. The Hopf bifurcation surfaces of (I)m=0 are obtained, and the sketch of Hopf bifurcation surfaces of (I)n=0 are drawn.     

Approximation by Classical Orthogonal Polynomials with Weight in Spaces L2,γ(a,b) and Widths of Some Functional Classes

Russian Mathematics - We investigate approximations of functions of classes W2(Dγ;(a,b)), r = 2, 3, …, by classical orthogonal polynomials with a weight γ in the spaces...     

On the Best Degree of Approximation by Euler (E,q)-Means

Let f(x)∈L_(2π) and its Fourier series by f(x)～α_0/2+sum from n=1 to ∞(α_ncosnx+b_nsinx)≡sum from n=0 to ∞(A_n(x)). Denote by S_n (f,x) its partial sums and by E_n~q(f,x) its Euler (E, q)-means, i. e. E_n~q(f,x)=1/(1+q)~π sum from m=0 to n((?)q~(n-m)S_m(f,x)), with q≥0 (E_n~0≡S_n). In [1] Holland and Sahney proved the following theorem. THEOREM A Ifω(f,t) is the modulus of continuity of f∈C_(2π), then the degree of approximation of f by the (E,q)-means of f is givens by##特殊公式未编改     

由y=Asin(ωx φ_0)到y=Asin(ωx φ_1)的图象变换方法

由 ｙ =Ａｓｉｎ(ωｘ φ0 )到 ｙ =Ａｓｉｎ(ωｘ φ1 )的图象变换是一种左右平移变换 ,即把ｙ=Ａｓｉｎ(ωｘ φ0 )图象上所有点向左或向右平移一定单位后得到 ｙ =Ａｓｉｎ(ωｘ φ1 )的图象 .要进行这一平移变换 ,必须确定平移方向和平移单位 .而确定平移单位和方向通常采用以下方法 .1　增量法函数图象向左或向右平移 ,可以看作是由图象上所有点的横坐标增加或减少相同的量引起的 ,亦即当 ｙ =Ａｓｉｎ(ωｘ φ0 )中的自变量ｘ产生一个增量Δｘ后 ,得到 ｙ =Ａｓｉｎ(ωｘ φ1 )的图象 .故有ω(ｘ Δｘ) φ0 =ωｘ φ1 ,∴Δ…