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Abelian groups from random hypergraphs 随机超图中的阿贝尔群
4区 数学
Combinatorics, Probability & Computing Pub Date : 2023-04-20 DOI: 10.1017/s0963548323000056
Andrew Newman
{"title":"Abelian groups from random hypergraphs","authors":"Andrew Newman","doi":"10.1017/s0963548323000056","DOIUrl":"https://doi.org/10.1017/s0963548323000056","url":null,"abstract":"Abstract For a $k$ -uniform hypergraph $mathcal{H}$ on vertex set ${1, ldots, n}$ we associate a particular signed incidence matrix $M(mathcal{H})$ over the integers. For $mathcal{H} sim mathcal{H}_k(n, p)$ an Erdős–Rényi random $k$ -uniform hypergraph, ${mathrm{coker}}(M(mathcal{H}))$ is then a model for random abelian groups. Motivated by conjectures from the study of random simplicial complexes we show that for $p = omega (1/n^{k - 1})$ , ${mathrm{coker}}(M(mathcal{H}))$ is torsion-free.","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135568825","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}
引用次数: 0
Poset Ramsey numbers: large Boolean lattice versus a fixed poset 偏序集拉姆齐数:大布尔格与固定偏序集的对比
4区 数学
Combinatorics, Probability & Computing Pub Date : 2023-02-17 DOI: 10.1017/s0963548323000032
Maria Axenovich, Christian Winter
{"title":"Poset Ramsey numbers: large Boolean lattice versus a fixed poset","authors":"Maria Axenovich, Christian Winter","doi":"10.1017/s0963548323000032","DOIUrl":"https://doi.org/10.1017/s0963548323000032","url":null,"abstract":"Abstract Given partially ordered sets (posets) $(P, leq _P!)$ and $(P^{prime}, leq _{P^{prime}}!)$ , we say that $P^{prime}$ contains a copy of $P$ if for some injective function $f,:, Prightarrow P^{prime}$ and for any $X, Yin P$ , $Xleq _P Y$ if and only if $f(X)leq _{P^{prime}} f(Y)$ . For any posets $P$ and $Q$ , the poset Ramsey number $R(P,Q)$ is the least positive integer $N$ such that no matter how the elements of an $N$ -dimensional Boolean lattice are coloured in blue and red, there is either a copy of $P$ with all blue elements or a copy of $Q$ with all red elements. We focus on a poset Ramsey number $R(P, Q_n)$ for a fixed poset $P$ and an $n$ -dimensional Boolean lattice $Q_n$ , as $n$ grows large. We show a sharp jump in behaviour of this number as a function of $n$ depending on whether or not $P$ contains a copy of either a poset $V$ , that is a poset on elements $A, B, C$ such that $Bgt C$ , $Agt C$ , and $A$ and $B$ incomparable, or a poset $Lambda$ , its symmetric counterpart. Specifically, we prove that if $P$ contains a copy of $V$ or $Lambda$ then $R(P, Q_n) geq n +frac{1}{15} frac{n}{log n}$ . Otherwise $R(P, Q_n) leq n + c(P)$ for a constant $c(P)$ . This gives the first non-marginal improvement of a lower bound on poset Ramsey numbers and as a consequence gives $R(Q_2, Q_n) = n + Theta left(frac{n}{log n}right)$ .","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135340270","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}
引用次数: 5
Multiple random walks on graphs: mixing few to cover many 图上的多次随机游走:混合少量以覆盖大量
4区 数学
Combinatorics, Probability & Computing Pub Date : 2023-02-15 DOI: 10.1017/s0963548322000372
Nicolás Rivera, Thomas Sauerwald, John Sylvester
{"title":"Multiple random walks on graphs: mixing few to cover many","authors":"Nicolás Rivera, Thomas Sauerwald, John Sylvester","doi":"10.1017/s0963548322000372","DOIUrl":"https://doi.org/10.1017/s0963548322000372","url":null,"abstract":"Abstract Random walks on graphs are an essential primitive for many randomised algorithms and stochastic processes. It is natural to ask how much can be gained by running $k$ multiple random walks independently and in parallel. Although the cover time of multiple walks has been investigated for many natural networks, the problem of finding a general characterisation of multiple cover times for worst-case start vertices (posed by Alon, Avin, Koucký, Kozma, Lotker and Tuttle in 2008) remains an open problem. First, we improve and tighten various bounds on the stationary cover time when $k$ random walks start from vertices sampled from the stationary distribution. For example, we prove an unconditional lower bound of $Omega ((n/k) log n)$ on the stationary cover time, holding for any $n$ -vertex graph $G$ and any $1 leq k =o(nlog n )$ . Secondly, we establish the stationary cover times of multiple walks on several fundamental networks up to constant factors. Thirdly, we present a framework characterising worst-case cover times in terms of stationary cover times and a novel, relaxed notion of mixing time for multiple walks called the partial mixing time . Roughly speaking, the partial mixing time only requires a specific portion of all random walks to be mixed. Using these new concepts, we can establish (or recover) the worst-case cover times for many networks including expanders, preferential attachment graphs, grids, binary trees and hypercubes.","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135582542","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}
引用次数: 6
Random feedback shift registers and the limit distribution for largest cycle lengths 随机反馈移位寄存器和最大周期长度的极限分布
4区 数学
Combinatorics, Probability & Computing Pub Date : 2023-02-14 DOI: 10.1017/s0963548323000020
Richard Arratia, E. Rodney Canfield, Alfred W. Hales
{"title":"Random feedback shift registers and the limit distribution for largest cycle lengths","authors":"Richard Arratia, E. Rodney Canfield, Alfred W. Hales","doi":"10.1017/s0963548323000020","DOIUrl":"https://doi.org/10.1017/s0963548323000020","url":null,"abstract":"Abstract For a random binary noncoalescing feedback shift register of width $n$ , with all $2^{2^{n-1}}$ possible feedback functions $f$ equally likely, the process of long cycle lengths, scaled by dividing by $N=2^n$ , converges in distribution to the same Poisson–Dirichlet limit as holds for random permutations in $mathcal{S}_N$ , with all $N!$ possible permutations equally likely. Such behaviour was conjectured by Golomb, Welch and Goldstein in 1959.","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135727870","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}
引用次数: 0
Bipartite-ness under smooth conditions 光滑条件下的双方性
4区 数学
Combinatorics, Probability & Computing Pub Date : 2023-02-03 DOI: 10.1017/s0963548323000019
Tao Jiang, Sean Longbrake, Jie Ma
{"title":"Bipartite-ness under smooth conditions","authors":"Tao Jiang, Sean Longbrake, Jie Ma","doi":"10.1017/s0963548323000019","DOIUrl":"https://doi.org/10.1017/s0963548323000019","url":null,"abstract":"Abstract Given a family \u0000$mathcal{F}$\u0000 of bipartite graphs, the Zarankiewicz number \u0000$z(m,n,mathcal{F})$\u0000 is the maximum number of edges in an \u0000$m$\u0000 by \u0000$n$\u0000 bipartite graph \u0000$G$\u0000 that does not contain any member of \u0000$mathcal{F}$\u0000 as a subgraph (such \u0000$G$\u0000 is called \u0000$mathcal{F}$\u0000 -free). For \u0000$1leq beta lt alpha lt 2$\u0000 , a family \u0000$mathcal{F}$\u0000 of bipartite graphs is \u0000$(alpha,beta )$\u0000 -smooth if for some \u0000$rho gt 0$\u0000 and every \u0000$mleq n$\u0000 , \u0000$z(m,n,mathcal{F})=rho m n^{alpha -1}+O(n^beta )$\u0000 . Motivated by their work on a conjecture of Erdős and Simonovits on compactness and a classic result of Andrásfai, Erdős and Sós, Allen, Keevash, Sudakov and Verstraëte proved that for any \u0000$(alpha,beta )$\u0000 -smooth family \u0000$mathcal{F}$\u0000 , there exists \u0000$k_0$\u0000 such that for all odd \u0000$kgeq k_0$\u0000 and sufficiently large \u0000$n$\u0000 , any \u0000$n$\u0000 -vertex \u0000$mathcal{F}cup {C_k}$\u0000 -free graph with minimum degree at least \u0000$rho (frac{2n}{5}+o(n))^{alpha -1}$\u0000 is bipartite. In this paper, we strengthen their result by showing that for every real \u0000$delta gt 0$\u0000 , there exists \u0000$k_0$\u0000 such that for all odd \u0000$kgeq k_0$\u0000 and sufficiently large \u0000$n$\u0000 , any \u0000$n$\u0000 -vertex \u0000$mathcal{F}cup {C_k}$\u0000 -free graph with minimum degree at least \u0000$delta n^{alpha -1}$\u0000 is bipartite. Furthermore, our result holds under a more relaxed notion of smoothness, which include the families \u0000$mathcal{F}$\u0000 consisting of the single graph \u0000$K_{s,t}$\u0000 when \u0000$tgg s$\u0000 . We also prove an analogous result for \u0000$C_{2ell }$\u0000 -free graphs for every \u0000$ell geq 2$\u0000 , which complements a result of Keevash, Sudakov and Verstraëte.","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135206022","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}
引用次数: 3
Off-diagonal book Ramsey numbers 非对角线书拉姆齐号码
4区 数学
Combinatorics, Probability & Computing Pub Date : 2023-01-09 DOI: 10.1017/s0963548322000360
David Conlon, Jacob Fox, Yuval Wigderson
{"title":"Off-diagonal book Ramsey numbers","authors":"David Conlon, Jacob Fox, Yuval Wigderson","doi":"10.1017/s0963548322000360","DOIUrl":"https://doi.org/10.1017/s0963548322000360","url":null,"abstract":"Abstract The book graph $B_n ^{(k)}$ consists of $n$ copies of $K_{k+1}$ joined along a common $K_k$ . In the prequel to this paper, we studied the diagonal Ramsey number $r(B_n ^{(k)}, B_n ^{(k)})$ . Here we consider the natural off-diagonal variant $r(B_{cn} ^{(k)}, B_n^{(k)})$ for fixed $c in (0,1]$ . In this more general setting, we show that an interesting dichotomy emerges: for very small $c$ , a simple $k$ -partite construction dictates the Ramsey function and all nearly-extremal colourings are close to being $k$ -partite, while, for $c$ bounded away from $0$ , random colourings of an appropriate density are asymptotically optimal and all nearly-extremal colourings are quasirandom. Our investigations also open up a range of questions about what happens for intermediate values of $c$ .","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136377500","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}
引用次数: 6
Sparse recovery properties of discrete random matrices 离散随机矩阵的稀疏恢复性质
IF 0.9 4区 数学
Combinatorics, Probability & Computing Pub Date : 2022-03-11 DOI: 10.1017/S0963548322000256
Asaf Ferber, A. Sah, Mehtaab Sawhney, Yizhe Zhu
{"title":"Sparse recovery properties of discrete random matrices","authors":"Asaf Ferber, A. Sah, Mehtaab Sawhney, Yizhe Zhu","doi":"10.1017/S0963548322000256","DOIUrl":"https://doi.org/10.1017/S0963548322000256","url":null,"abstract":"\u0000\t <jats:p>Motivated by problems from compressed sensing, we determine the threshold behaviour of a random <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000256_inline1.png\" />\u0000\t\t<jats:tex-math>\u0000$ntimes d pm 1$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> matrix <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000256_inline2.png\" />\u0000\t\t<jats:tex-math>\u0000$M_{n,d}$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> with respect to the property ‘every <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000256_inline3.png\" />\u0000\t\t<jats:tex-math>\u0000$s$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> columns are linearly independent’. In particular, we show that for every <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000256_inline4.png\" />\u0000\t\t<jats:tex-math>\u0000$0lt delta lt 1$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> and <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000256_inline5.png\" />\u0000\t\t<jats:tex-math>\u0000$s=(1-delta )n$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula>, if <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000256_inline6.png\" />\u0000\t\t<jats:tex-math>\u0000$dleq n^{1+1/2(1-delta )-o(1)}$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> then with high probability every <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000256_inline7.png\" />\u0000\t\t<jats:tex-math>\u0000$s$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> columns of <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000256_inline8.png\" />\u0000\t\t<jats:tex-math>\u0000$M_{n,d}$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> are linearly independent, and if <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000256_inline9.png\" />\u0000\t\t<jats:tex-math>\u0000$dgeq n^{1+1/2(1-delta )+o(1)}$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> then with high probability there are some <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graph","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86934360","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}
引用次数: 0
Improved bound for improper colourings of graphs with no odd clique minor 改进了无奇小团图不正确着色的界
IF 0.9 4区 数学
Combinatorics, Probability & Computing Pub Date : 2022-03-05 DOI: 10.1017/s0963548322000268
R. Steiner
{"title":"Improved bound for improper colourings of graphs with no odd clique minor","authors":"R. Steiner","doi":"10.1017/s0963548322000268","DOIUrl":"https://doi.org/10.1017/s0963548322000268","url":null,"abstract":"\u0000 Strengthening Hadwiger’s conjecture, Gerards and Seymour conjectured in 1995 that every graph with no odd \u0000 \u0000 \u0000 \u0000$K_t$\u0000\u0000 \u0000 -minor is properly \u0000 \u0000 \u0000 \u0000$(t-1)$\u0000\u0000 \u0000 -colourable. This is known as the Odd Hadwiger’s conjecture. We prove a relaxation of the above conjecture, namely we show that every graph with no odd \u0000 \u0000 \u0000 \u0000$K_t$\u0000\u0000 \u0000 -minor admits a vertex \u0000 \u0000 \u0000 \u0000$(2t-2)$\u0000\u0000 \u0000 -colouring such that all monochromatic components have size at most \u0000 \u0000 \u0000 \u0000$lceil frac{1}{2}(t-2) rceil$\u0000\u0000 \u0000 . The bound on the number of colours is optimal up to a factor of \u0000 \u0000 \u0000 \u0000$2$\u0000\u0000 \u0000 , improves previous bounds for the same problem by Kawarabayashi (2008, Combin. Probab. Comput.17 815–821), Kang and Oum (2019, Combin. Probab. Comput.28 740–754), Liu and Wood (2021, arXiv preprint, arXiv:1905.09495), and strengthens a result by van den Heuvel and Wood (2018, J. Lond. Math. Soc.98 129–148), who showed that the above conclusion holds under the more restrictive assumption that the graph is \u0000 \u0000 \u0000 \u0000$K_t$\u0000\u0000 \u0000 -minor-free. In addition, the bound on the component-size in our result is much smaller than those of previous results, in which the dependency on \u0000 \u0000 \u0000 \u0000$t$\u0000\u0000 \u0000 was given by a function arising from the graph minor structure theorem of Robertson and Seymour. Our short proof combines the method by van den Heuvel and Wood for \u0000 \u0000 \u0000 \u0000$K_t$\u0000\u0000 \u0000 -minor-free graphs with some additional ideas, which make the extension to odd \u0000 \u0000 \u0000 \u0000$K_t$\u0000\u0000 \u0000 -minor-free graphs possible.","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74933860","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}
引用次数: 2
Hypergraphs without non-trivial intersecting subgraphs 没有非平凡相交子图的超图
IF 0.9 4区 数学
Combinatorics, Probability & Computing Pub Date : 2022-01-01 DOI: 10.1017/S096354832200013X
Xizhi Liu
{"title":"Hypergraphs without non-trivial intersecting subgraphs","authors":"Xizhi Liu","doi":"10.1017/S096354832200013X","DOIUrl":"https://doi.org/10.1017/S096354832200013X","url":null,"abstract":"A hypergraph F is non-trivial intersecting if every pair of edges in it have a nonempty intersection, but no vertex is contained in all edges of F . Mubayi and Verstraëte showed that for every k ≥ d + 1 ≥ 3 and n ≥ ( d + 1) k / d every k -graph H on n vertices without a non-trivial intersecting subgraph of size d + 1 contains at most (cid:2) n − 1 k − 1 (cid:3) edges. They conjectured that the same conclusion holds for all d ≥ k ≥ 4 and sufficiently large n . We confirm their conjecture by proving a stronger statement. They also conjectured that for m ≥ 4 and sufficiently large n the maximum size of a 3-graph on n vertices without a non-trivial intersecting subgraph of size 3 m + 1 is achieved by certain Steiner triple systems. We give a construction with more edges showing that their conjecture is not true in general.","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75445155","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}
引用次数: 0
Approximately symmetric forms far from being exactly symmetric 近似对称的形式远不是完全对称的
IF 0.9 4区 数学
Combinatorics, Probability & Computing Pub Date : 2021-12-29 DOI: 10.1017/s0963548322000244
L. Mili'cevi'c
{"title":"Approximately symmetric forms far from being exactly symmetric","authors":"L. Mili'cevi'c","doi":"10.1017/s0963548322000244","DOIUrl":"https://doi.org/10.1017/s0963548322000244","url":null,"abstract":"\u0000\t <jats:p>Let <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000244_inline1.png\" />\u0000\t\t<jats:tex-math>\u0000$V$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> be a finite-dimensional vector space over <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000244_inline2.png\" />\u0000\t\t<jats:tex-math>\u0000$mathbb{F}_p$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula>. We say that a multilinear form <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000244_inline3.png\" />\u0000\t\t<jats:tex-math>\u0000$alpha colon V^k to mathbb{F}_p$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> in <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000244_inline4.png\" />\u0000\t\t<jats:tex-math>\u0000$k$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> variables is <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000244_inline5.png\" />\u0000\t\t<jats:tex-math>\u0000$d$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula>-<jats:italic>approximately symmetric</jats:italic> if the partition rank of difference <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000244_inline6.png\" />\u0000\t\t<jats:tex-math>\u0000$alpha (x_1, ldots, x_k) - alpha (x_{pi (1)}, ldots, x_{pi (k)})$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> is at most <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000244_inline7.png\" />\u0000\t\t<jats:tex-math>\u0000$d$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> for every permutation <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000244_inline8.png\" />\u0000\t\t<jats:tex-math>\u0000$pi in textrm{Sym}_k$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula>. In a work concerning the inverse theorem for the Gowers uniformity <jats:inline-formula>\u0000\t <jats:alternatives>\u0000\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548322000244_inline9.png\" />\u0000\t\t<jats:tex-math>\u0000$|!cdot! |_{mathsf{U}^4}$\u0000</jats:tex-math>\u0000\t </jats:alternatives>\u0000\t </jats:inline-formula> norm in the case of low characteristic, Tidor conjectured that any <jats:inline-formula>\u0000\t","PeriodicalId":10513,"journal":{"name":"Combinatorics, Probability & Computing","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72492977","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}
引用次数: 3
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