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| 芯片构型的稳定遵循一种“最小作用原理”的形式:每个顶点在稳定过程中不超过必要的崩塌量。 | | 芯片构型的稳定遵循一种“最小作用原理”的形式:每个顶点在稳定过程中不超过必要的崩塌量。 |
− | ==[[用户:Zcy|Zcy]]([[用户讨论:Zcy|讨论]])chip configurations的翻译存疑==[[用户:Zcy|Zcy]]([[用户讨论:Zcy|讨论]]) | + | |
| + | ==[[用户:Zcy|Zcy]]([[用户讨论:Zcy|讨论]])chip configurations的翻译存疑==[[用户:Zcy|Zcy]]([[用户讨论:Zcy|讨论]]) |
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| This can be formalized as follows. Call a sequence of topples ''legal'' if it only topples unstable vertices, and ''stabilizing'' if it results in a stable configuration. The standard way of stabilizing the sandpile is to find a maximal legal sequence; i.e., by toppling so long as it is possible. Such a sequence is obviously stabilizing, and the Abelian property of the sandpile is that all such sequences are equivalent up to permutation of the toppling order; that is, for any vertex <math>v</math>, the number of times <math>v</math> topples is the same in all legal stabilizing sequences. According to the least action principle, a '''minimal stabilizing''' sequence is also equivalent up to permutation of the toppling order to a legal (and still stabilizing) sequence. In particular, the configuration resulting from a minimal stabilizing sequence is the same as results from a maximal legal sequence. | | This can be formalized as follows. Call a sequence of topples ''legal'' if it only topples unstable vertices, and ''stabilizing'' if it results in a stable configuration. The standard way of stabilizing the sandpile is to find a maximal legal sequence; i.e., by toppling so long as it is possible. Such a sequence is obviously stabilizing, and the Abelian property of the sandpile is that all such sequences are equivalent up to permutation of the toppling order; that is, for any vertex <math>v</math>, the number of times <math>v</math> topples is the same in all legal stabilizing sequences. According to the least action principle, a '''minimal stabilizing''' sequence is also equivalent up to permutation of the toppling order to a legal (and still stabilizing) sequence. In particular, the configuration resulting from a minimal stabilizing sequence is the same as results from a maximal legal sequence. |
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| ==[[用户:Zcy|Zcy]]([[用户讨论:Zcy|讨论]])<math>\mathbf{n}</math> is an integral vector (not necessarily non-negative)这一句话的翻译存疑。 | | ==[[用户:Zcy|Zcy]]([[用户讨论:Zcy|讨论]])<math>\mathbf{n}</math> is an integral vector (not necessarily non-negative)这一句话的翻译存疑。 |
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− | === Scaling limits缩放限制=== | + | ===缩放限制=== |
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| [[File:Scaling sandpile identity.gif|thumb|Animation of the sandpile identity on square grids of increasing size. Black color denotes vertices with 0 grains, green is for 1, purple is for 2, and gold is for 3.]] | | [[File:Scaling sandpile identity.gif|thumb|Animation of the sandpile identity on square grids of increasing size. Black color denotes vertices with 0 grains, green is for 1, purple is for 2, and gold is for 3.]] |
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| [[File:Scaling sandpile identity.gif|thumb|沙堆标识在方形网格不断增加的动画。 黑色表示沙粒数为0的顶点,绿色表示沙粒数为1,紫色表示沙粒数为2,金色表示沙粒数为3。]] | | [[File:Scaling sandpile identity.gif|thumb|沙堆标识在方形网格不断增加的动画。 黑色表示沙粒数为0的顶点,绿色表示沙粒数为1,紫色表示沙粒数为2,金色表示沙粒数为3。]] |
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− | The animation shows the recurrent configuration corresponding to the identity of the sandpile group on different <math>N\times N</math> square grids of increasing sizes <math>N\geq 1</math>, whereby the configurations are rescaled to always have the same physical dimension. Visually, the identities on larger grids seem to become more and more detailed and to "converge to a continuous image". Mathematically, this suggests the existence of scaling-limits of the sandpile identity on square grids based on the notion of weak-* convergence (or some other, generalized notion of convergence). Indeed, existence of scaling limits of recurrent sandpile configurations has been proved by Wesley Pegden and Charles Smart
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− | <ref name=Pegden2016>{{cite arxiv |last1=Pegden |first1=Wesley |last2=Smart |first2=Charles |title=Stability of patterns in the Abelian sandpile.|eprint=1708.09432 | date=2017 | ref=Pegden2017|class=math.AP }}</ref>
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− | .<ref name=Pegden2013>{{cite journal |last1=Pegden |first1=Wesley |last2=Smart |first2=Charles |title=Convergence of the Abelian sandpile |journal=Duke Mathematical Journal |date=2013 |volume=162 |issue=4 |pages=627–642 |doi=10.1215/00127094-2079677 |ref=Pegden2013|arxiv=1105.0111 |s2cid=13027232 }}</ref> In further joint work with Lionel Levine, they use the scaling limit to explain the fractal structure of the sandpile on square grids.<ref name=Levine2016>{{cite journal |last1=Levine |first1=Lionel |last2=Pegden |first2=Wesley |title=Apollonian structure in the Abelian sandpile |journal=Geometric and Functional Analysis |date=2016 |volume=26 |issue=1 |pages=306–336 |doi=10.1007/s00039-016-0358-7 |ref=Levine2016|hdl=1721.1/106972 |s2cid=119626417 |hdl-access=free }}</ref>
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| 动画显示了对应网格尺寸<math>N\geq 1</math>不断增大,不同大小的<math>N\times N</math>正方形网格上的沙堆群标识的重复构型,从而重新缩放构型,使其最终具有相同的物理尺度。从视觉上看,更大网格上的标识似乎变得越来越详细,并且“收敛到一个连续的图像”。从数学上讲,这表明基于弱收敛的概念(或其他一些广义的收敛概念),正方形网格上沙堆恒等式存在标度极限。事实上,Wesley-Pegden和Charles-Smart已经证明了循环沙堆结构标度极限的存在性。<ref name=Pegden2016>{{cite arxiv |last1=Pegden |first1=Wesley |last2=Smart |first2=Charles |title=Stability of patterns in the Abelian sandpile.|eprint=1708.09432 | date=2017 | ref=Pegden2017|class=math.AP }}</ref> | | 动画显示了对应网格尺寸<math>N\geq 1</math>不断增大,不同大小的<math>N\times N</math>正方形网格上的沙堆群标识的重复构型,从而重新缩放构型,使其最终具有相同的物理尺度。从视觉上看,更大网格上的标识似乎变得越来越详细,并且“收敛到一个连续的图像”。从数学上讲,这表明基于弱收敛的概念(或其他一些广义的收敛概念),正方形网格上沙堆恒等式存在标度极限。事实上,Wesley-Pegden和Charles-Smart已经证明了循环沙堆结构标度极限的存在性。<ref name=Pegden2016>{{cite arxiv |last1=Pegden |first1=Wesley |last2=Smart |first2=Charles |title=Stability of patterns in the Abelian sandpile.|eprint=1708.09432 | date=2017 | ref=Pegden2017|class=math.AP }}</ref> |
| .<ref name=Pegden2013>{{cite journal |last1=Pegden |first1=Wesley |last2=Smart |first2=Charles |title=Convergence of the Abelian sandpile |journal=Duke Mathematical Journal |date=2013 |volume=162 |issue=4 |pages=627–642 |doi=10.1215/00127094-2079677 |ref=Pegden2013|arxiv=1105.0111 |s2cid=13027232 }}</ref> In further joint work with Lionel Levine, they use the scaling limit to explain the fractal structure of the sandpile on square grids.<ref name=Levine2016>{{cite journal |last1=Levine |first1=Lionel |last2=Pegden |first2=Wesley |title=Apollonian structure in the Abelian sandpile |journal=Geometric and Functional Analysis |date=2016 |volume=26 |issue=1 |pages=306–336 |doi=10.1007/s00039-016-0358-7 |ref=Levine2016|hdl=1721.1/106972 |s2cid=119626417 |hdl-access=free }}</ref> | | .<ref name=Pegden2013>{{cite journal |last1=Pegden |first1=Wesley |last2=Smart |first2=Charles |title=Convergence of the Abelian sandpile |journal=Duke Mathematical Journal |date=2013 |volume=162 |issue=4 |pages=627–642 |doi=10.1215/00127094-2079677 |ref=Pegden2013|arxiv=1105.0111 |s2cid=13027232 }}</ref> In further joint work with Lionel Levine, they use the scaling limit to explain the fractal structure of the sandpile on square grids.<ref name=Levine2016>{{cite journal |last1=Levine |first1=Lionel |last2=Pegden |first2=Wesley |title=Apollonian structure in the Abelian sandpile |journal=Geometric and Functional Analysis |date=2016 |volume=26 |issue=1 |pages=306–336 |doi=10.1007/s00039-016-0358-7 |ref=Levine2016|hdl=1721.1/106972 |s2cid=119626417 |hdl-access=free }}</ref> |
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− | ==[[用户:Zcy|Zcy]]([[用户讨论:Zcy|讨论]])whereby the configurations are rescaled to always have the same physical dimension翻译存疑 | + | ==[[用户:Zcy|Zcy]]([[用户讨论:Zcy|讨论]])whereby the configurations are rescaled to always have the same physical dimension翻译存疑 ==[[用户:Zcy|Zcy]]([[用户讨论:Zcy|讨论]]) |
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| == Generalizations and related models归纳与相关模型== | | == Generalizations and related models归纳与相关模型== |