<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article  PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="3.0" xml:lang="en" article-type="research article"><front><journal-meta><journal-id journal-id-type="publisher-id">JAMP</journal-id><journal-title-group><journal-title>Journal of Applied Mathematics and Physics</journal-title></journal-title-group><issn pub-type="epub">2327-4352</issn><publisher><publisher-name>Scientific Research Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.4236/jamp.2014.24006</article-id><article-id pub-id-type="publisher-id">JAMP-43971</article-id><article-categories><subj-group subj-group-type="heading"><subject>Articles</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Physics&amp;Mathematics</subject></subj-group></article-categories><title-group><article-title>
 
 
  Classification of All Single Traveling Wave Solutions to (3 + 1)-Dimensional Breaking Soliton Equation
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>ang</surname><given-names>Li</given-names></name><xref ref-type="aff" rid="aff1"><sub>1</sub></xref><xref ref-type="corresp" rid="cor1"><sup>*</sup></xref></contrib></contrib-group><aff id="aff1"><label>1</label><addr-line>Department of Mathematics, Northeast Petroleum University, Daqing, China</addr-line></aff><author-notes><corresp id="cor1">* E-mail:<email>liyang120918@163.com</email></corresp></author-notes><pub-date pub-type="epub"><day>05</day><month>03</month><year>2014</year></pub-date><volume>02</volume><issue>04</issue><fpage>41</fpage><lpage>45</lpage><history><date date-type="received"><day>15</day>	<month>February</month>	<year>2014</year></date><date date-type="rev-recd"><day>10</day>	<month>March</month>	<year>2014</year>	</date><date date-type="accepted"><day>17</day>	<month>March</month>	<year>2014</year></date></history><permissions><copyright-statement>&#169; Copyright  2014 by authors and Scientific Research Publishing Inc. </copyright-statement><copyright-year>2014</copyright-year><license><license-p>This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/</license-p></license></permissions><abstract><p>
 
 
   In order to get the exact traveling wave solutions to nonlinear partial differential equation, the complete discrimination system for polynomial and direct integral method are applied to the considered equation. All single traveling wave solutions to the equation can be obtained. As an example, we give the solutions to (3 + 1)-dimensional breaking soliton equation.  
 
</p></abstract><kwd-group><kwd>The Nonlinear Partial Differential Equation; Complete Discrimination System for Polynomial; Direct Integral Method; Traveling Wave Transform; (3 + 1)-Dimensional Breaking Soliton Equation</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>Keywords</title><p>The Nonlinear Partial Differential Equation; Complete Discrimination System for Polynomial; Direct Integral Method; Traveling Wave Transform; (3 + 1)-Dimensional Breaking Soliton Equation</p><p><img src="htmlimages\6-1720111x\26db8b1f-a9d8-435b-8244-91338b086028.png" /></p></sec><sec id="s2"><title>1. Introduction</title><p>For the past decades, to deal with nonlinear partial differential equations (PDEs), many methods have been developed. These methods have been widely applied to many PDEs to obtain the exact solutions. Recently, a method named the complete discrimination system for polynomial method has been proposed by Liu [<xref ref-type="bibr" rid="scirp.43971-ref1">1</xref>] -[<xref ref-type="bibr" rid="scirp.43971-ref5">5</xref>] . By Liu’s method, we can obtain the classification of single traveling wave solutions to some PDEs. For the PDE being considered, we take the traveling wave transformation and integrate it. The PDE can be directly reduced to ordinary differential equation (ODE) which can be turned into the integral form as follows:</p><disp-formula id="scirp.43971-formula120395"><label>(1)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\d5fdd455-22b1-4dff-93de-7ae813ed4229.png"  xlink:type="simple"/></disp-formula><p>where <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\231c8df0-0f44-4663-8af8-5123995e3f2c.png" xlink:type="simple"/></inline-formula> is a n-th order polynomial. By Liu’s method, we can obtain the classification of all solutions to the Equation (1).</p><p>In this paper, we take into account (3 + 1)-dimensional breaking soliton equation, and it reads as</p><disp-formula id="scirp.43971-formula120396"><label>(2)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\b60fac90-81c0-4ba2-8b30-0f878d29900f.png"  xlink:type="simple"/></disp-formula><p>where a, b, c, d and e are arbitrary constants.</p><p>Equation (2) was originally proposed by Lin [<xref ref-type="bibr" rid="scirp.43971-ref6">6</xref>] to study the Virasoro-type symmetry algebra. Li [<xref ref-type="bibr" rid="scirp.43971-ref7">7</xref>] got some solitary wave solutions and periodic wave solutions of Equation (2) by using a simple transformation relation and solving the ordinary differential equation. Shi [<xref ref-type="bibr" rid="scirp.43971-ref8">8</xref>] gave some exact solutions of Equation (2) by turning it into KdV equation though introducing a simple transformation, and so on.</p></sec><sec id="s3"><title>2. Classification</title><p>For Equation (2), we take the traveling wave transformation<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\006748a5-20bd-49c5-8589-69f52a0c51b4.png" xlink:type="simple"/></inline-formula>, and can obtain the corresponding reduced ODE as follow</p><disp-formula id="scirp.43971-formula120397"><label>(3)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\838cfa0a-0242-4e9b-a9a6-9e0afb8c4ffc.png"  xlink:type="simple"/></disp-formula><p>Integrating Equation (3) with respect to <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\614880b8-924c-42f9-b608-370941964547.png" xlink:type="simple"/></inline-formula> once , we simplify it and yield</p><disp-formula id="scirp.43971-formula120398"><label>(4)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\0d55b1f3-7aa2-43c3-b90c-4437fe78a66b.png"  xlink:type="simple"/></disp-formula><p>where <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\8f97f358-55bb-4f84-8006-f4f48d6c601c.png" xlink:type="simple"/></inline-formula> is an integral constant.</p><p>Let</p><disp-formula id="scirp.43971-formula120399"><label>(5)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\becde556-fb6b-45b3-b6e3-147a166e583a.png"  xlink:type="simple"/></disp-formula><p>Then we have</p><disp-formula id="scirp.43971-formula120400"><label>(6)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\dcb4a450-fa64-4aa5-938b-fb9141b2dcd0.png"  xlink:type="simple"/></disp-formula><p>Or equivalently</p><disp-formula id="scirp.43971-formula120401"><label>(7)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\1d51c3b1-db88-43e1-bfa0-784d0fd8a52d.png"  xlink:type="simple"/></disp-formula><p>Integrating the Equation (7) once with respect to<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\d1bc15da-0577-4821-b8c7-1bd8237d800e.png" xlink:type="simple"/></inline-formula>, we get</p><disp-formula id="scirp.43971-formula120402"><label>(8)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\761c04c0-4f29-4aa7-9df4-5ce5f52f6899.png"  xlink:type="simple"/></disp-formula><p>where <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\8b9669fe-ae4b-4645-945e-e0cbd34d735a.png" xlink:type="simple"/></inline-formula> is an integral constant. For purpose of use the complete discrimination system for the third order polynomial, we have the following solving process.</p><p>Let</p><disp-formula id="scirp.43971-formula120403"><label>(9)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\3eade328-1818-486c-b7ca-0e78986ec029.png"  xlink:type="simple"/></disp-formula><p>Then Equation (8) becomes</p><disp-formula id="scirp.43971-formula120404"><label>(10)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\49d709e7-eac2-4a30-9f4a-91b9c60f0449.png"  xlink:type="simple"/></disp-formula><p>where<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\b25f3c0d-ae18-4669-a117-aaf18d853f4e.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\989d218e-93aa-4005-bc31-82bda612c8e2.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\e3fbfd1d-9505-4fc6-80fb-90d6e86bc209.png" xlink:type="simple"/></inline-formula>and <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\c847680f-1438-4b8c-9faf-161d12e09d06.png" xlink:type="simple"/></inline-formula> is a function of<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\5ae11491-b8ac-441c-a052-6efe5b911c11.png" xlink:type="simple"/></inline-formula>. The integral form of Equation (8) is</p><disp-formula id="scirp.43971-formula120405"><label>(11)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\cc6571fa-e9d5-44d0-9e49-c5d8981ab260.png"  xlink:type="simple"/></disp-formula><p>Denote</p><disp-formula id="scirp.43971-formula120406"><label>(12)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\7e9d93e2-06a8-4d02-8c31-9e6ba95fd782.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.43971-formula120407"><label>(13)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\60e80849-2a1c-49fa-9cfd-e303f09269a0.png"  xlink:type="simple"/></disp-formula><p>According to the complete discrimination system, we give the corresponding single traveling wave solutions to Equation (2).</p><p>Case 1. <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\958275f0-3ba7-4d93-86ad-60e4f24a539e.png" xlink:type="simple"/></inline-formula>has a double real root and a simple real root. Then we have</p><disp-formula id="scirp.43971-formula120408"><label>(14)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\5f0eae2b-0c93-48d1-9306-e86eb274a1b2.png"  xlink:type="simple"/></disp-formula><p>When<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\64a5579e-1392-4f1a-b291-5c73b1884e09.png" xlink:type="simple"/></inline-formula>, the solutions to Equation (8) are as follows</p><disp-formula id="scirp.43971-formula120409"><label>(15)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\e4726680-03f6-4cc5-a4e6-f38566f94025.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.43971-formula120410"><label>(16)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\8ab908e2-8f3c-492a-8fb7-549d54728f30.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.43971-formula120411"><label>(17)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\e187d753-ef9b-43cc-abb0-15960daa028b.png"  xlink:type="simple"/></disp-formula><p>The corresponding solutions to Equation (2) are</p><disp-formula id="scirp.43971-formula120412"><label>(18)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\79b602ea-35bf-4865-ba3d-aef0be68dae6.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.43971-formula120413"><label>(19)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\79924bf4-049d-4c7f-9660-4dd0d858b6a5.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.43971-formula120414"><label>(20)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\f5878be4-8374-4168-8319-3baff0fae1cc.png"  xlink:type="simple"/></disp-formula><p>Case 2. <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\10db81f1-92af-43f8-8021-f851ab767c34.png" xlink:type="simple"/></inline-formula>has a triple root. Then we have</p><disp-formula id="scirp.43971-formula120415"><label>(21)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\cf9420f4-8752-4fd7-8f99-143d970df15a.png"  xlink:type="simple"/></disp-formula><p>The corresponding solution to Equation (2) is</p><disp-formula id="scirp.43971-formula120416"><label>(22)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\5b1825de-5a20-4616-adeb-9aeade0c4c7d.png"  xlink:type="simple"/></disp-formula><p>Case 3. <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\8017c1b2-55e7-4129-babf-a33a2b03159a.png" xlink:type="simple"/></inline-formula>has three different real roots. Then we have</p><disp-formula id="scirp.43971-formula120417"><label>(23)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\08d0893a-d90b-4c62-bad6-1baa82d75d75.png"  xlink:type="simple"/></disp-formula><p>When<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\e56aff59-658c-4315-8d7e-993ff94d3036.png" xlink:type="simple"/></inline-formula>, the corresponding solutions to Equation (2) is</p><disp-formula id="scirp.43971-formula120418"><label>(24)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\37efa788-03a6-44cd-977f-874b0caa5ba8.png"  xlink:type="simple"/></disp-formula><p>When<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\1d8b121d-1727-484c-83fb-a1081585e513.png" xlink:type="simple"/></inline-formula>, the corresponding solutions to Equation (2) is</p><disp-formula id="scirp.43971-formula120419"><label>(25)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\0e03ea01-f848-459f-af7f-540469b7735c.png"  xlink:type="simple"/></disp-formula><p>where<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\0b92e530-8033-45f5-a9fb-6c963e688b4f.png" xlink:type="simple"/></inline-formula>.</p><p>Case 4. <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\e6be96ab-a7ad-4933-8810-f29b2cbfccd0.png" xlink:type="simple"/></inline-formula>has only a real root. Then we have</p><disp-formula id="scirp.43971-formula120420"><label>(26)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\3e285c7b-5b27-4051-9c44-95a2563ab6d3.png"  xlink:type="simple"/></disp-formula><p>When<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\697ea235-91d4-42c4-869b-bf4d00f66b10.png" xlink:type="simple"/></inline-formula>, the corresponding solutions to Equation (2) is</p><disp-formula id="scirp.43971-formula120421"><label>(27)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\adf98cca-e665-49df-a15b-497f66f55817.png"  xlink:type="simple"/></disp-formula><p>where<inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\7d855d51-2498-4af1-96bb-ced4ae53b168.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\19b9b836-f836-4a1e-9fd7-dc822ba90322.png" xlink:type="simple"/></inline-formula>are integral constants in Equations (18)-(20), (22), (24), (25) and (27).</p><p>In Equations (24) (25) and (27), we give the expression of some signals as follow</p><disp-formula id="scirp.43971-formula120422"><label>(28)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\74b8ec4a-19c9-4f3c-b5f5-834c8d4261ab.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.43971-formula120423"><label>(29)</label><graphic position="anchor" xlink:href="htmlimages\6-1720111x\59da129e-be68-4293-b847-9a27296c7411.png"  xlink:type="simple"/></disp-formula><p>The solutions <inline-formula><inline-graphic xlink:href="tmlimages\6-1720111x\022c83be-3e24-4ad7-9a25-dda9096014ef.png" xlink:type="simple"/></inline-formula> are all possible exact traveling wave solutions to Equation (2). We can see it is easy to write the corresponding solutions to (3 + 1)-dimensional breaking soliton equation.</p></sec><sec id="s4"><title>3. Conclusion</title><p>From the descriptions above, we use the complete discrimination system for polynomial and direct integral method to obtain all possible traveling wave solutions to (3 + 1)-dimensional breaking soliton equation. This method is direct and effective. With the same method, some of other equations can be dealt with.</p></sec><sec id="s5"><title>Acknowledgements</title><p>I would like to thank the referees for their valuable suggestions.</p></sec></body><back><ref-list><title>References</title><ref id="scirp.43971-ref1"><label>1</label><mixed-citation publication-type="other" xlink:type="simple">Liu, C.S. (2007) Classification of All Single Travelling Wave Solutions to Calogero-Degasperis-Focas Equation. 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