{"title":"C N $\\mathbb {C}^N$ 中具有任意零势符号的 2 非enerate real hypersurfaces 的新示例","authors":"Martin Kolář, Ilya Kossovskiy, David Sykes","doi":"10.1112/jlms.12962","DOIUrl":null,"url":null,"abstract":"<p>We introduce a class of uniformly 2-nondegenerate CR hypersurfaces in <span></span><math>\n <semantics>\n <msup>\n <mi>C</mi>\n <mi>N</mi>\n </msup>\n <annotation>$\\mathbb {C}^N$</annotation>\n </semantics></math>, for <span></span><math>\n <semantics>\n <mrow>\n <mi>N</mi>\n <mo>></mo>\n <mn>3</mn>\n </mrow>\n <annotation>$N&gt;3$</annotation>\n </semantics></math>, having a rank 1 Levi kernel. The class is first of all remarkable by the fact that for every <span></span><math>\n <semantics>\n <mrow>\n <mi>N</mi>\n <mo>></mo>\n <mn>3</mn>\n </mrow>\n <annotation>$N&gt;3$</annotation>\n </semantics></math> it forms an <i>explicit</i> infinite-dimensional family of everywhere 2-nondegenerate hypersurfaces. To the best of our knowledge, this is the first such construction. Besides, the class contains infinite-dimensional families of nonequivalent structures having a given constant nilpotent CR symbol for every such symbol. Using methods that are able to handle all cases with <span></span><math>\n <semantics>\n <mrow>\n <mi>N</mi>\n <mo>></mo>\n <mn>5</mn>\n </mrow>\n <annotation>$N&gt;5$</annotation>\n </semantics></math> simultaneously, we solve the equivalence problem for the considered structures whose symbol is represented by a single Jordan block, classify their algebras of infinitesimal symmetries, and classify the locally homogeneous structures among them. We show that the remaining considered structures, which have symbols represented by a direct sum of Jordan blocks, can be constructed from the single block structures through simple linking and extension processes.</p>","PeriodicalId":49989,"journal":{"name":"Journal of the London Mathematical Society-Second Series","volume":"110 2","pages":""},"PeriodicalIF":1.0000,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"New examples of 2-nondegenerate real hypersurfaces in \\n \\n \\n C\\n N\\n \\n $\\\\mathbb {C}^N$\\n with arbitrary nilpotent symbols\",\"authors\":\"Martin Kolář, Ilya Kossovskiy, David Sykes\",\"doi\":\"10.1112/jlms.12962\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We introduce a class of uniformly 2-nondegenerate CR hypersurfaces in <span></span><math>\\n <semantics>\\n <msup>\\n <mi>C</mi>\\n <mi>N</mi>\\n </msup>\\n <annotation>$\\\\mathbb {C}^N$</annotation>\\n </semantics></math>, for <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>N</mi>\\n <mo>></mo>\\n <mn>3</mn>\\n </mrow>\\n <annotation>$N&gt;3$</annotation>\\n </semantics></math>, having a rank 1 Levi kernel. The class is first of all remarkable by the fact that for every <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>N</mi>\\n <mo>></mo>\\n <mn>3</mn>\\n </mrow>\\n <annotation>$N&gt;3$</annotation>\\n </semantics></math> it forms an <i>explicit</i> infinite-dimensional family of everywhere 2-nondegenerate hypersurfaces. To the best of our knowledge, this is the first such construction. Besides, the class contains infinite-dimensional families of nonequivalent structures having a given constant nilpotent CR symbol for every such symbol. Using methods that are able to handle all cases with <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>N</mi>\\n <mo>></mo>\\n <mn>5</mn>\\n </mrow>\\n <annotation>$N&gt;5$</annotation>\\n </semantics></math> simultaneously, we solve the equivalence problem for the considered structures whose symbol is represented by a single Jordan block, classify their algebras of infinitesimal symmetries, and classify the locally homogeneous structures among them. 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引用次数: 0
摘要
我们介绍一类在 C N $\mathbb {C}^N$ 中,对于 N > 3 $N>3$,具有秩 1 Levi 内核的均匀 2 非enerate CR 超曲面。该类的显著特点首先在于,对于每个 N > 3 $N>3$,它构成了一个明确的无穷维无处不在的 2 非enerate 超曲面族。据我们所知,这是第一个这样的构造。此外,该类还包含了非等价结构的无穷维族,这些非等价结构的每个符号都有一个给定的常无势 CR 符号。我们使用能够同时处理 N > 5 $N>5$ 的所有情况的方法,解决了所考虑的符号由单个乔丹块表示的结构的等价性问题,对它们的无穷小对称性布拉进行了分类,并对其中的局部同质结构进行了分类。我们证明,其余符号由约旦块直接相加表示的结构可以通过简单的链接和扩展过程从单块结构中构造出来。
New examples of 2-nondegenerate real hypersurfaces in
C
N
$\mathbb {C}^N$
with arbitrary nilpotent symbols
We introduce a class of uniformly 2-nondegenerate CR hypersurfaces in , for , having a rank 1 Levi kernel. The class is first of all remarkable by the fact that for every it forms an explicit infinite-dimensional family of everywhere 2-nondegenerate hypersurfaces. To the best of our knowledge, this is the first such construction. Besides, the class contains infinite-dimensional families of nonequivalent structures having a given constant nilpotent CR symbol for every such symbol. Using methods that are able to handle all cases with simultaneously, we solve the equivalence problem for the considered structures whose symbol is represented by a single Jordan block, classify their algebras of infinitesimal symmetries, and classify the locally homogeneous structures among them. We show that the remaining considered structures, which have symbols represented by a direct sum of Jordan blocks, can be constructed from the single block structures through simple linking and extension processes.
期刊介绍:
The Journal of the London Mathematical Society has been publishing leading research in a broad range of mathematical subject areas since 1926. The Journal welcomes papers on subjects of general interest that represent a significant advance in mathematical knowledge, as well as submissions that are deemed to stimulate new interest and research activity.