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Proof of Riemann Conjecture Based on Contradiction between Xi-Function and Its Product Expression
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作者 chuanmiao chen 《Advances in Pure Mathematics》 2023年第7期463-472,共10页
Riemann proved three results: analytically continue ζ(s) over the whole complex plane s =σ + it with a pole s =1;(Theorem A) functional equation ξ(t) = G(s<sub>0</sub>)ζ (s<sub>0</sub>), s&... Riemann proved three results: analytically continue ζ(s) over the whole complex plane s =σ + it with a pole s =1;(Theorem A) functional equation ξ(t) = G(s<sub>0</sub>)ζ (s<sub>0</sub>), s<sub>0</sub> =1/2 + it and (Theorem B) product expression ξ<sub>1</sub>(t) by all roots of ξ(t). He stated Riemann conjecture (RC): All roots of ξ (t) are real. We find a mistake of Riemann: he used the same notation ξ(t) in two theorems. Theorem B must contain complex roots;it conflicts with RC. Thus theorem B can only be used by contradiction. Our research can be completed on s<sub>0</sub> =1/2 + it. Using all real roots r<sub>k</sub><sub> </sub>and (true) complex roots z<sub>j</sub> = t<sub>j</sub> + ia<sub>j</sub> of ξ (z), define product expressions w(t), w(0) =ξ(0) and Q(t) > 0, Q(0) =1 respectively, so ξ<sub>1</sub>(t) = w(t)Q(t). Define infinite point-set L(ω) = {t : t ≥10 and |ζ(s<sub>0</sub>)| =ω} for small ω > 0. If ξ(t) has complex roots, then ω =ωQ(t) on L(ω). Finally in a large interval of the first module |z<sub>1</sub>|>>1, we can find many points t ∈ L(ω) to make Q(t) . This contraction proves RC. In addition, Riemann hypothesis (RH) ζ for also holds, but it cannot be proved by ζ. 展开更多
关键词 Riemann Conjecture Xi-Function Functional Equation Product Expression Multiplicative Group CONTRADICTION
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Geometric Proof of Riemann Conjecture (Continued) 被引量:2
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作者 chuanmiao chen 《Advances in Pure Mathematics》 2021年第9期771-783,共13页
This paper will prove Riemann conjecture(RC): All zeros of <span style="white-space:nowrap;"><span style="white-space:nowrap;"><em>ξ</em></span>(<span style="... This paper will prove Riemann conjecture(RC): All zeros of <span style="white-space:nowrap;"><span style="white-space:nowrap;"><em>ξ</em></span>(<span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><em>τ</em></span></span></span></span>)</span> lie on critical line. Denote <img src="Edit_189dc2b2-73ef-4036-9f06-ecf8a47fe58b.png" width="140" height="16" alt="" />, and <img src="Edit_a8ec55cb-e4c4-4156-ba23-ae01a31d1bc8.png" width="110" height="22" alt="" /> on critical line. We have found two mysteries in Riemann’s paper. <em>The first mystery</em> is the equivalence: <img src="Edit_3c075830-3c6c-4a23-9851-5b7d219e8000.png" width="140" height="21" alt="" /> is uniquely determined by its initial value <span style="white-space:nowrap;"><em>u</em> (<em>t</em>)</span>. <em>The second mystery</em> is Riemamm conjecture 2 (RC2): Using all zeros <span style="white-space:nowrap;"><em>t<sub>j</sub> </em></span>of <em>u</em> (<em>t</em>) can uniquely express <img src="Edit_b15d9c18-b55b-49e3-97a1-d2e03ccb6343.png" width="175" height="23" alt="" />. We find that the proof of RC is hidden in it. Our basic idea as follows. Consider functional equation <img src="Edit_f5295ff4-90b2-4465-851a-cad140b181c8.png" width="305" height="20" alt="" />. It is known that on critical line <img src="Edit_b45bff49-6d09-456b-9d1f-4259c66293d3.png" width="310" height="23" alt="" /> and <img src="Edit_4182ba79-0fcb-4f84-b7e7-c7574406596e.png" width="85" height="26" alt="" />, then we have the upper bound of growth <img src="Edit_d3d84d75-cc56-47b8-a9a7-ef8a9a5f07b1.png" width="250" height="33" alt="" /> To prove RC2 (or RC), by contradiction. If <span style="white-space:nowrap;"><em>ξ</em>(<em>τ</em>)</span> has conjugate complex roots <em>t</em>'<span style="white-space:nowrap;">±<em>i</em><span style="white-space:nowrap;"><em>β</em></span>'’</span>, <span style="white-space:nowrap;"><em>β</em>'>0</span>, <em>R</em><sup>2</sup>=t'<sup>2</sup>+<span style="white-space:nowrap;"><em>β</em>'<sup>2</sup></span>, by symmetry <span style="white-space:nowrap;"><em>ξ</em>(<em>τ</em>)=<span style="white-space:nowrap;"><em>ξ</em>(-<em>τ</em>)</span></span>, then -(<em>t</em>'<span style="white-space:nowrap;">±<em>i</em><em>β</em>''</span>) do yet. So <em>ξ</em> must contain four factors. Then <em>u</em>(<em>t</em>) contains a real factor <img src="Edit_ac03c1a5-0480-4efa-aac4-7788852a42a9.png" width="225" height="22" alt="" /> and <span style="white-space:nowrap;">ln|<em>u</em>(<em>t</em>)|</span> contains a term (the lower bound) <img src="Edit_6e94ad71-a310-4717-99ee-90384b0d89ba.png" width="230" height="19" alt="" /> which contradicts to the growth above. So <span style="white-space:nowrap;"><em>ξ</em></span> can not have the complex roots and <em>u</em>(<em>t</em>) does not have the factor <em>p</em>(<em>t</em>). Therefore both RC2 and RC are proved. We have seen that the two-dimensional problem is reduced to one-dimension and the one-dimensional <span style="white-space:nowrap;"><em>u</em>(<em>t</em>)</span> is reduced to its product expression. Perhaps this is close to the original idea of Riemann. Other results are also discussed by geometric analysis in the last section. 展开更多
关键词 RC EQUIVALENCE RC2 Product Expression Single Peak Multiple Zeros
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Geometric Proof of Riemann Conjecture 被引量:1
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作者 chuanmiao chen 《Advances in Pure Mathematics》 2021年第4期334-345,共12页
This paper proves Riemann conjecture (RH), <em>i.e</em>., that all the zeros in critical region of Riemann <span style="white-space:nowrap;"><em><span style="white-space:nowra... This paper proves Riemann conjecture (RH), <em>i.e</em>., that all the zeros in critical region of Riemann <span style="white-space:nowrap;"><em><span style="white-space:nowrap;"><em>ξ</em><span style="white-space:normal;"> </span></span></em></span>-function lie on symmetric line <span style="white-space:nowrap;"><em>σ</em></span> =1/2 . Its proof is based on two important properties: the symmetry and alternative oscillation for <span style="white-space:nowrap;"><em><em>ξ</em><span style="white-space:normal;"> </span></em>=<em> u </em>+<em> iv</em></span> . Denote <img src="Edit_317839cd-bad0-44d8-b081-c473bcb336f1.png" width="170" height="15" alt="" />. Riemann proved that u is real and <em>v</em> <span style="white-space:nowrap;">≡ </span>0 for <span style="white-space:nowrap;"><em><span style="white-space:nowrap;">β</span></em> =0</span> (the symmetry). We prove that the zeros of u and v for <em>β</em> <span style="white-space:nowrap;">> 0</span> are alternative, so <span style="white-space:nowrap;"><em>u</em> (<em>t</em>,0)</span> is the single peak. A geometric model was proposed. <img src="Edit_27688061-de42-4bce-ad80-6fb3dd1e3d4b.png" width="85" height="27" alt="" /> is called the root-interval of <em>u </em>(<em>t</em>,<em style="white-space:normal;">β</em>) , if |<span style="white-space:nowrap;"><em>u</em>| <em>> </em>0</span> is inside <em>I</em><sub><em>j</em> </sub>and <span style="white-space:nowrap;"><em>u</em> = 0</span> is at its two ends. If |<em>u</em> (<em style="white-space:normal;">t</em><span style="white-space:normal;">,</span><em style="white-space:normal;">β</em>)| has only one peak on each <em style="white-space:normal;">I</em><sub style="white-space:normal;"><em>j</em></sub>, which is called the single peak, else called multiple peaks (it will be proved that the multiple peaks do not exist). The important expressions of u and v for <em style="white-space:normal;">β</em><span style="white-space:normal;"> </span>> 0 were derived. By <img src="Edit_b6369c2e-6a6d-4e1a-8a75-00d743cecaf1.png" width="240" height="28" alt="" />, the peak <em style="white-space:normal;">u </em><span style="white-space:normal;">(</span><em style="white-space:normal;">t</em><span style="white-space:normal;">,</span><em style="white-space:normal;">β</em><span style="white-space:normal;">)</span> will develop toward its convex direction. Besides, <em style="white-space:normal;">u<sub>t</sub> </em><span style="white-space:normal;">(</span><em style="white-space:normal;">t</em><span style="white-space:normal;">,</span><em style="white-space:normal;">β</em><span style="white-space:normal;">)</span> has opposite signs at two ends <em>t</em> = <em>t<sub>j</sub></em><sub> </sub>, <em>t<sub>j+1</sub></em> of <em>I<sub>j </sub></em>, <img src="Edit_be3f0d63-1d24-4165-ac2c-141c9a47d1c8.png" width="145" height="28" alt="" /> also does, then there exists some inner point <span style="white-space:nowrap;"><em>t</em>′</span> such that <span style="white-space:nowrap;"><em>v</em><em></em> (<em>t′</em>,<em>β</em>) = 0</span>. Therefore {|<em>u</em>|,|<em>v</em>|/<em>β</em>} in <em>I<sub>j</sub></em><sub> </sub>form a peak-valley structure such that <img src="Edit_70bb530a-662f-464a-b3c8-4d5625fbf679.png" width="180" height="22" alt="" /> has positive lower bound independent of <em>t</em> <span style="white-space:nowrap;">∈ </span><em>I<sub>j</sub></em><sub> </sub>(<em>i.e</em>. RH holds in <em style="white-space:normal;">I<sub>j</sub></em><sub style="white-space:normal;"> </sub>). As <em style="white-space:normal;">u </em><span style="white-space:normal;">(</span><em style="white-space:normal;">t</em><span style="white-space:normal;">,</span><em style="white-space:normal;">β</em><span style="white-space:normal;">)</span> does not have the finite condensation point (unless <span style="white-space:nowrap;"><em>u</em> = <em>cons</em><em>t</em>.</span>), any finite t surely falls in some <em style="white-space:normal;">I<sub>j</sub></em><sub style="white-space:normal;"> </sub>, then <img src="Edit_166a9981-aac8-476b-a29a-496763297b35.png" width="50" height="23" alt="" /> holds for any t (RH is proved). Our previous paper “Local geometric proof of Riemann conjecture” (APM, V.10:8, 2020) has two defects, this paper has amended these defects and given a complete proof of RH. 展开更多
关键词 Riemann Conjecture Geometric Analysis SYMMETRY Alternative Oscillation Single Peak Peak-Valley Structure
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Local Geometric Proof of Riemann Conjecture 被引量:1
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作者 chuanmiao chen 《Advances in Pure Mathematics》 2020年第10期589-610,共22页
Riemann hypothesis (RH) is a difficult problem. So far one doesn’t know how to go about it. Studying <i>ζ</i> and using analysis method likely are two incor-rect guides. Actually, a unique hope may study... Riemann hypothesis (RH) is a difficult problem. So far one doesn’t know how to go about it. Studying <i>ζ</i> and using analysis method likely are two incor-rect guides. Actually, a unique hope may study Riemann function <img alt="" src="Edit_8fcdfff5-6b95-42a4-8f47-2cabe2723dfc.bmp" />, <img alt="" src="Edit_6ce3a4bd-4c68-49e5-aabe-dec3e904e282.bmp" />, <img alt="" src="Edit_29ea252e-a81e-4b21-a41c-09209c780bb2.bmp" /> by geometric analysis, which has the symmetry: v=0 if <i>β</i>=0, and basic expression <img alt="" src="Edit_bc7a883f-312d-44fd-bcdd-00f25c92f80a.bmp" />. We show that |u| is single peak in each root-interval <img alt="" src="Edit_d7ca54c7-4866-4419-a4bd-cbb808b365af.bmp" /> of <i>u</i> for fixed <em>β</em> ∈(0,1/2]. Using the slope u<sub>t</sub>, we prove that <i>v</i> has opposite signs at two end-points of I<sub>j</sub>. There surely exists an inner point such that , so {|u|,|v|/<em>β</em>} form a local peak-valley structure, and have positive lower bound <img alt="" src="Edit_bac1a5f6-673e-49b6-892c-5adff0141376.bmp" /> in I<sub>j</sub>. Because each <i>t</i> must lie in some I<sub>j</sub>, then ||<em>ξ</em>|| > 0 is valid for any <i>t</i> (<i>i.e.</i> RH is true). Using the positivity <img alt="" src="Edit_83c3d2cf-aa7e-4aba-89f5-0eb44659918a.bmp" /> of Lagarias (1999), we show the strict monotone <img alt="" src="Edit_87eb4e9e-bc7b-43e3-b316-5dcf0efaf0d5.bmp" /> for <i>β</i> > <i>β</i><sub>0</sub> ≥ 0 , and the peak-valley structure is equiva-lent to RH, which may be the geometric model expected by Bombieri (2000). This research follows Liuhui’s methodology: “Computing can detect the un-known and method”.</i> 展开更多
关键词 Riemann Conjecture Local Geometric Proof Symmetry Peak-Valley Struc-ture EQUIVALENCE Liuhui’s Methodology
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Proof of Riemann Conjecture 被引量:1
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作者 chuanmiao chen 《Advances in Pure Mathematics》 2022年第5期374-391,共18页
Using translation β = σ &#8722;1/2 and rotation s =σ + it = 1/2 + iz, z = t &#8722;iβ, Riemann got two results: (Theorem A) the functional equation ξ(z) = G(s)ξ(s), where , and (Theorem B) the product ex... Using translation β = σ &#8722;1/2 and rotation s =σ + it = 1/2 + iz, z = t &#8722;iβ, Riemann got two results: (Theorem A) the functional equation ξ(z) = G(s)ξ(s), where , and (Theorem B) the product expression , where z<sub>j</sub> are all roots of ξ(z), including complex roots. He proposed Riemann conjecture (RC): All roots of ξ(z) are real. As the product expression can only be used as a tool of contradiction, we prove RC by contradiction. To avoid the zeros of ξ(1/2 + it), define a subset . We have basic estimate , on L (R). One can construct by all real roots t<sub>j</sub> of ξ(t). If ξ has no complex roots, then w(t) = G(s)ξ(s) for s = 1/2 + it. If the product expression has a complex root z'=t' &#8722;iα, where 0 a ≤ 1/2, R' = |z′| > 10, then ξ(z) has four complex roots ±(t′ ± iα), and should contain fourth order factor p(z), i.e. ξ(z) = w(z)p(z). But p(z) can not be contained in ξ(s), as we have on L(R) and p(t) ≥ 0.5(t/R)<sup>4</sup> . As a result, we can rewrite ξ(t) = w(t)p(t) =G(s)ξ(s)p(t) on and get This contradicts the basic estimate. Therefore ξ(z) has no complex roots and RC holds. 展开更多
关键词 Riemann Conjecture Distribution of Zeros Entire Function SYMMETRY Functional Equation Product Expression
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Superconvergence of Continuous Finite Elements with Interpolated Coeffcients for Initial Value Problems of Nonlinear Ordinary Differential Equation
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作者 Zhiguang Xiong chuanmiao chen 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2007年第1期37-44,共8页
In this paper, n-degree continuous finite element method with interpolated coefficients for nonlinear initial value problem of ordinary differential equation is introduced and analyzed. An optimal superconvergence u-u... In this paper, n-degree continuous finite element method with interpolated coefficients for nonlinear initial value problem of ordinary differential equation is introduced and analyzed. An optimal superconvergence u-uh = O(hn+2), n ≥ 2, at (n + 1)-order Lobatto points in each element respectively is proved. Finally the theoretical results are tested by a numerical example. 展开更多
关键词 超收敛 有限元 原始价值 常微分方程
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The Symmetry of Riemann <i>ξ</i>-Function
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作者 chuanmiao chen 《Advances in Pure Mathematics》 2020年第8期464-470,共7页
To prove RH, studying <span style="white-space:nowrap;"><em>ζ</em> </span>and using pure analysis method likely are two kinds of the incorrect guide. Actually, a unique hope may stud... To prove RH, studying <span style="white-space:nowrap;"><em>ζ</em> </span>and using pure analysis method likely are two kinds of the incorrect guide. Actually, a unique hope may study Riemann function <img src="Edit_b4e53620-7ae2-4a2b-aee0-351c62aef8cd.png" width="250" height="20" alt="" /> by geometric analysis, which has the symmetry: <span style="white-space:nowrap;"><em>v</em></span> = 0 if <span style="white-space:nowrap;"><em>β</em></span> = 0, and <img src="Edit_8c67c5d7-c1d4-4cad-8792-78e4bd172ebd.png" width="150" height="28" alt="" /> Assume that |<em>u</em>| is single peak in each root-interval <img src="Edit_a91df253-2965-4b03-8033-54aba2e23036.png" width="85" height="27" alt="" /> of <em>u</em> for any fixed <span style="white-space:nowrap;"><em>β</em></span> <span style="white-space:nowrap;">∈ (0,1/2]</span>, using the slope <em>u</em><sub><em>t </em></sub>of the single peak, we prove that <em>v</em> has opposite signs at two end-points of <em>I</em><sub><em>j</em></sub>, there surely is an inner point so that <em>v</em> = 0, so {|<em>u</em>|,|<em>v</em>|/<span style="white-space:nowrap;"><em>β</em></span>}form a local peak-valley structure, and have positive lower bound <img src="Edit_04798c0f-8e21-4a3a-ae12-0e28b01ee348.png" width="167" height="22" alt="" />in <em>I</em><sub><em>j</em></sub>. Because each <em>t</em> must lie in some <em style="white-space:normal;">I</em><sub style="white-space:normal;"><em>j</em></sub> , then ||<span style="white-space:nowrap;"><em>ξ</em></span>|| > 0 is valid for any <em>t</em>. In this way, the summation process of <span style="white-space:nowrap;"><em>ξ</em></span> is avoided. We have proved the main theorem: Assume that <em>u</em> (<em>t</em>, <span style="white-space:nowrap;"><em>β</em></span>) is single peak, then RH is valid for any <img src="Edit_ed8521a3-63b1-417f-a3b0-a3c790bae519.png" width="140" height="19" alt="" />. If using the equivalence of Lagarias (1999), the assumption of single peak can be canceled. Therefore our new thinking is that we have found the local peak-valley structure of <span style="white-space:nowrap;"><em>ξ</em></span>, which may be the geometry structure expected by Bombieri (2000), and proposed a basic framework of proving RH by geometric analysis. 展开更多
关键词 Riemann ξ-Function SYMMETRY Peak-Valley Structure Single Peak RH
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ON EXTRAPOLATION CASCADIC MULTIGRID METHOD 被引量:11
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作者 chuanmiao chen Zhong-Ci Shi Hongling Hu 《Journal of Computational Mathematics》 SCIE CSCD 2011年第6期684-697,共14页
关键词 瀑布型多重网格法 外推算法 有限元素 渐近展开 二次插值 数值试验 初始值 非线性
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FINITE ELEMENT METHOD WITH SUPERCONVERGENCE FOR NONLINEAR HAMILTONIAN SYSTEMS 被引量:4
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作者 chuanmiao chen Qiong Tang Shufang Hu 《Journal of Computational Mathematics》 SCIE CSCD 2011年第2期167-184,共18页
这份报纸从三个方面为非线性的 Hamiltonian 系统涉及有限元素方法:精力, symplicity,和全球错误的保存。学习有限元素方法的 symplecticity,我们使用所有分析方法而非通常使用的代数学的方法。我们在节点 t 证明集中的顺序最佳[n ]... 这份报纸从三个方面为非线性的 Hamiltonian 系统涉及有限元素方法:精力, symplicity,和全球错误的保存。学习有限元素方法的 symplecticity,我们使用所有分析方法而非通常使用的代数学的方法。我们在节点 t 证明集中的顺序最佳[n ] 在中间长的时间并且表明高精确性的 symplecticity。证明强烈取决于 superconvergence 分析。数字实验证明建议方法能保存精力很好并且能也在长时间使全球轨道错误小。[从作者抽象] 展开更多
关键词 HAMILTON系统 非线性 超收敛 有限元法 有限元方法 哈密顿系统 收敛性分析 代数方法
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TIME-EXTRAPOLATION ALGORITHM (TEA) FOR LINEAR PARABOLIC PROBLEMS 被引量:2
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作者 Hongling Hu chuanmiao chen Kejia Pan 《Journal of Computational Mathematics》 SCIE CSCD 2014年第2期183-194,共12页
伪制服上的 Crank-Nicolson 计划的快答案协调因为寓言的问题被讨论。到答案的减少整齐要求,首先,一些新错误估计被证明。第二,我们分析寓言的分离计划的二个特征,并且发现 Multigrid 方法(MG ) 的效率极大地被减少。数字实验比较... 伪制服上的 Crank-Nicolson 计划的快答案协调因为寓言的问题被讨论。到答案的减少整齐要求,首先,一些新错误估计被证明。第二,我们分析寓言的分离计划的二个特征,并且发现 Multigrid 方法(MG ) 的效率极大地被减少。数字实验比较效率直接结合坡度方法(DCG ) 和推测 Cascadic Multigrid 方法(EXCMG ) 。最后,我们建议一个时间推测算法(茶) ,它作为好起始的价值拿以前的几个水平答案的线性联合加速集中的率。一些典型推测公式数字地被比较。并且我们发现在某些精确性要求下面,为 3 顺序和 7 水平推测公式的 CG 重复计数关于 DCG 的的 1/3。因为 TEA 算法独立于空间尺寸,它为伪制服网孔仍然是有效的。当仅仅最好的格子被需要,建议方法被考虑为非线性的寓言的问题很有效。[从作者抽象] 展开更多
关键词 非线性抛物问题 TEA算法 外推算法 多重网格法 均匀网格 共轭梯度法 误差估计 离散格式
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Superconvergence for triangular cubic elements 被引量:2
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作者 chuanmiao chen Jicheng Jin Shi Shu 《Chinese Science Bulletin》 SCIE EI CAS 1999年第1期47-49,共3页
A new structure of superconvergence for the cubic triangular finite element approximation u/2 to a second-order elliptic problem Au=f is studied based on some orthogonal expansions in an interval. Suppose that Ω is a... A new structure of superconvergence for the cubic triangular finite element approximation u/2 to a second-order elliptic problem Au=f is studied based on some orthogonal expansions in an interval. Suppose that Ω is a convex polygonal domain with boundary L, its triangulation is uniform and T<sub>h</sub> is a set of vertexes and side midpoints of all elements. Then u<sub>h</sub> itself has no superconvergence points in Ω, while in any interior subdomain Ω<sub>0</sub> the average gradient Du<sub>h</sub> has superconvergence D(d<sub>h</sub>-u)=O(h<sup>m+1</sup>lnh) at z∈T<sub>h</sub>∩Ω<sub>0</sub>(no other superconvergence points). Furthermore, prescribe u=0 on L<sub>1</sub>.Then the superconvergence near L<sub>1</sub> will surely disappear; if αa<sub>v</sub>u+bu=0 on L<sub>3</sub>, where v is the conormal direction, the numercal experiments show superconvergence up to L<sub>3</sub>(the case of A=-Δ and b=0 has already been proved). 展开更多
关键词 SUPERCONVERGENCE TRIANGULAR CUBIC ELEMENT FINITE ELEMENT approxination.
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Implicit DG Method for Time Domain Maxwell’s Equations Involving Metamaterials 被引量:1
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作者 Jiangxing Wang Ziqing Xie chuanmiao chen 《Advances in Applied Mathematics and Mechanics》 SCIE 2015年第6期796-817,共22页
An implicit discontinuous Galerkin method is introduced to solve the timedomain Maxwell’s equations in metamaterials.The Maxwell’s equations in metamaterials are represented by integral-differential equations.Our sc... An implicit discontinuous Galerkin method is introduced to solve the timedomain Maxwell’s equations in metamaterials.The Maxwell’s equations in metamaterials are represented by integral-differential equations.Our scheme is based on discontinuous Galerkin method in spatial domain and Crank-Nicolson method in temporal domain.The fully discrete numerical scheme is proved to be unconditionally stable.When polynomial of degree at most p is used for spatial approximation,our scheme is verified to converge at a rate of O(τ^(2)+h^(p)+1/2).Numerical results in both 2D and 3D are provided to validate our theoretical prediction. 展开更多
关键词 Maxwell’s equations METAMATERIALS fully disctete DG method L2-stability L2-error estimate.
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An Extrapolation Cascadic MultigridMethod for Elliptic Problems on Reentrant Domains
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作者 Kejia Pan Dongdong He chuanmiao chen 《Advances in Applied Mathematics and Mechanics》 SCIE 2017年第6期1347-1363,共17页
This paper proposes an extrapolation cascadic multigrid(EXCMG)method to solve elliptic problems in domains with reentrant corners.On a class ofλ-graded meshes,we derive some new extrapolation formulas to construct a ... This paper proposes an extrapolation cascadic multigrid(EXCMG)method to solve elliptic problems in domains with reentrant corners.On a class ofλ-graded meshes,we derive some new extrapolation formulas to construct a high-order approximation to the finite element solution on the next finer mesh using the numerical solutions on two-level of grids(current and previous grids).Then,this high-order approximation is used as the initial guess to reduce computational cost of the conjugate gradient method.Recursive application of this idea results in the EXCMG method proposed in this paper.Finally,numerical results for a crack problem and an L-shaped problem are presented to verify the efficiency and effectiveness of the proposed EXCMG method. 展开更多
关键词 Richardson extrapolation Cascadicmultigrid gradedmesh elliptic problems corner singularity
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Numerical Integration over Pyramids
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作者 chuanmiao chen Michal Krızek Liping Liu 《Advances in Applied Mathematics and Mechanics》 SCIE 2013年第3期309-320,共12页
Pyramidal elements are often used to connect tetrahedral and hexahedral elements in the finite element method.In this paper we derive three new higher order numerical cubature formulae for pyramidal elements.
关键词 Reference pyramidal element nonlinear systems of algebraic equations Bramble-Hilbert lemma TRIANGULAR tetrahedral and pyramidal numbers
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