Pub Date : 2022-01-01DOI: 10.14232/ejqtde.2022.1.26
S. Stević
We present thirty-six classes of three-dimensional systems of difference equations of the hyperbolic-cotangent type which are solvable in closed form.
本文给出了36类可解的双曲-余切型三维差分方程组。
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Pub Date : 2022-01-01DOI: 10.14232/ejqtde.2022.1.34
P. Korman, D. Schmidt
<jats:p>We reduce solution of the Dirichlet problem (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns="http://www.w3.org/1998/Math/MathML"> <mml:mi>x</mml:mi> <mml:mo>∈<!-- ∈ --></mml:mo> <mml:mi>D</mml:mi> <mml:mo>⊂<!-- ⊂ --></mml:mo> <mml:msup> <mml:mi>R</mml:mi> <mml:mi>m</mml:mi> </mml:msup> </mml:math>) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns="http://www.w3.org/1998/Math/MathML" display="block"> <mml:mi mathvariant="normal">Δ<!-- Δ --></mml:mi> <mml:mi>u</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mo>+</mml:mo> <mml:mi>a</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mi>u</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mi>f</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mspace width="1em" /> <mml:mstyle displaystyle="false" scriptlevel="0"> <mml:mtext>in </mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>D</mml:mi> </mml:mrow> </mml:mstyle> <mml:mo>,</mml:mo> <mml:mspace width="2em" /> <mml:mi>u</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> <mml:mspace width="1em" /> <mml:mstyle displaystyle="false" scriptlevel="0"> <mml:mtext>on </mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">∂<!-- ∂ --></mml:mi> <mml:mi>D</mml:mi> </mml:mrow> </mml:mstyle> </mml:math> to iterative solution of a simpler problem <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns="http://www.w3.org/1998/Math/MathML" display="block"> <mml:mi mathvariant="normal">Δ<!-- Δ --></mml:mi> <mml:mi>u</mml:mi> <mml:mo>=</mml:mo> <mml:mi>f</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mspace width="thickmathspace" /> <mml:mspace width="thickmathspace" /> <mml:mstyle displaystyle="false" scriptlevel="0"> <mml:mtext>in </mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>D</mml:mi> </mml:mrow> </mml:mstyle> <mml:mo>,</mml:mo> <mml:mspace width="thickmathspace" /> <mml:mspace width="thickmathspace" /> <mml:mi>u</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> <mml:mspace width="thickmathspace" /> <mml:mspace width="thickmathspace" /> <mml:mstyle displaystyle="false" scriptlevel="0"> <mml:mtext>on </mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">∂<!-- ∂ --></mml:mi> <mml:mi>D</mml:mi> </mml:mrow> </mml:mstyle> <mml:mspace width="thinmathspace" /> <mml:mo>,</mml:mo> </mml:math> for which one can use either Fourier series or Green's function method. The method is suitable for numerical computations, particularly when one uses Newton's method for semilinear problems
我们将Dirichlet问题(x∈D∧R m) Δ u (x) + a (x) u (x) = f (x)在D中,u = 0在∂D中简化为一个更简单的问题Δ u = f (x)在D中,u = 0在∂D中,可以使用傅里叶级数或格林函数方法。该方法适用于数值计算,特别是当人们使用牛顿方法解决半线性问题Δ u + g (x, u) = 0在D中,u = 0在∂D中,。
{"title":"Iterative solution of elliptic equations","authors":"P. Korman, D. Schmidt","doi":"10.14232/ejqtde.2022.1.34","DOIUrl":"https://doi.org/10.14232/ejqtde.2022.1.34","url":null,"abstract":"<jats:p>We reduce solution of the Dirichlet problem (<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>x</mml:mi> <mml:mo>∈<!-- ∈ --></mml:mo> <mml:mi>D</mml:mi> <mml:mo>⊂<!-- ⊂ --></mml:mo> <mml:msup> <mml:mi>R</mml:mi> <mml:mi>m</mml:mi> </mml:msup> </mml:math>) <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns=\"http://www.w3.org/1998/Math/MathML\" display=\"block\"> <mml:mi mathvariant=\"normal\">Δ<!-- Δ --></mml:mi> <mml:mi>u</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mo>+</mml:mo> <mml:mi>a</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mi>u</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mo>=</mml:mo> <mml:mi>f</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mspace width=\"1em\" /> <mml:mstyle displaystyle=\"false\" scriptlevel=\"0\"> <mml:mtext>in </mml:mtext> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mi>D</mml:mi> </mml:mrow> </mml:mstyle> <mml:mo>,</mml:mo> <mml:mspace width=\"2em\" /> <mml:mi>u</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> <mml:mspace width=\"1em\" /> <mml:mstyle displaystyle=\"false\" scriptlevel=\"0\"> <mml:mtext>on </mml:mtext> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mi mathvariant=\"normal\">∂<!-- ∂ --></mml:mi> <mml:mi>D</mml:mi> </mml:mrow> </mml:mstyle> </mml:math> to iterative solution of a simpler problem <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns=\"http://www.w3.org/1998/Math/MathML\" display=\"block\"> <mml:mi mathvariant=\"normal\">Δ<!-- Δ --></mml:mi> <mml:mi>u</mml:mi> <mml:mo>=</mml:mo> <mml:mi>f</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mspace width=\"thickmathspace\" /> <mml:mspace width=\"thickmathspace\" /> <mml:mstyle displaystyle=\"false\" scriptlevel=\"0\"> <mml:mtext>in </mml:mtext> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mi>D</mml:mi> </mml:mrow> </mml:mstyle> <mml:mo>,</mml:mo> <mml:mspace width=\"thickmathspace\" /> <mml:mspace width=\"thickmathspace\" /> <mml:mi>u</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> <mml:mspace width=\"thickmathspace\" /> <mml:mspace width=\"thickmathspace\" /> <mml:mstyle displaystyle=\"false\" scriptlevel=\"0\"> <mml:mtext>on </mml:mtext> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mi mathvariant=\"normal\">∂<!-- ∂ --></mml:mi> <mml:mi>D</mml:mi> </mml:mrow> </mml:mstyle> <mml:mspace width=\"thinmathspace\" /> <mml:mo>,</mml:mo> </mml:math> for which one can use either Fourier series or Green's function method. The method is suitable for numerical computations, particularly when one uses Newton's method for semilinear problems ","PeriodicalId":50537,"journal":{"name":"Electronic Journal of Qualitative Theory of Differential Equations","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66584786","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}
Pub Date : 2022-01-01DOI: 10.14232/ejqtde.2022.1.47
Equations Jorge Rodríguez–López, R. Precup, C. Gheorghiu
The paper deals with the existence and localization of positive radial solutions for stationary partial differential equations involving a general ϕ -Laplace operator in the annulus. Three sets of boundary conditions are considered: Dirichlet–Neumann, Neumann–Dirichlet and Dirichlet–Dirichlet. The results are based on the homotopy version of Krasnosel'skii's fixed point theorem and Harnack type inequalities, first established for each one of the boundary conditions. As a consequence, the problem of multiple solutions is solved in a natural way. Numerical experiments confirming the theory, one for each of the three sets of boundary conditions, are performed by using the MATLAB object-oriented package Chebfun.
{"title":"On the localization and numerical computation of positive radial\u0000 solutions for \u0000 ϕ\u0000 \u0000 \u0000-Laplace equations in the annulus","authors":"\t\tEquations\t\t\tJorge Rodríguez–López, R. Precup, C. Gheorghiu","doi":"10.14232/ejqtde.2022.1.47","DOIUrl":"https://doi.org/10.14232/ejqtde.2022.1.47","url":null,"abstract":"The paper deals with the existence and localization of positive radial solutions for stationary partial differential equations involving a general ϕ -Laplace operator in the annulus. Three sets of boundary conditions are considered: Dirichlet–Neumann, Neumann–Dirichlet and Dirichlet–Dirichlet. The results are based on the homotopy version of Krasnosel'skii's fixed point theorem and Harnack type inequalities, first established for each one of the boundary conditions. As a consequence, the problem of multiple solutions is solved in a natural way. Numerical experiments confirming the theory, one for each of the three sets of boundary conditions, are performed by using the MATLAB object-oriented package Chebfun.","PeriodicalId":50537,"journal":{"name":"Electronic Journal of Qualitative Theory of Differential Equations","volume":"15 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81667728","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}