{"title":"Simple, local and subdirectly irreducible state residuated lattices","authors":"Mohammad Taheri, F. Khaksar Haghani, S. Rasouli","doi":"10.33044/revuma.1722","DOIUrl":"https://doi.org/10.33044/revuma.1722","url":null,"abstract":"","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44990814","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}
Carolina Araujo, Roya Beheshti, Ana-Maria Castravet, K. Jabbusch, Svetlana A. Makarova, Enrica Mazzon, Libby Taylor, Nived Viswanathan
. We address in this paper Fano manifolds with positive higher Chern characters, which are expected to enjoy stronger versions of several of the nice properties of Fano manifolds. For instance, they should be covered by higher dimensional rational varieties, and families of higher Fano manifolds over higher dimensional bases should admit meromorphic sections (modulo the Brauer obstruction). Aiming at finding new examples of higher Fano manifolds, we investigate positivity of higher Chern characters of rational homogeneous spaces. We determine which rational homogeneous spaces of Picard rank 1 have positive second Chern character, and show that the only rational homogeneous spaces of Picard rank 1 having positive second and third Chern characters are projective spaces and quadric hypersurfaces. We also classify Fano manifolds of large index having positive second and third Chern characters. We conclude by discussing conjectural characterizations of projective spaces and complete intersections in terms of these higher Fano conditions.
{"title":"Higher Fano manifolds","authors":"Carolina Araujo, Roya Beheshti, Ana-Maria Castravet, K. Jabbusch, Svetlana A. Makarova, Enrica Mazzon, Libby Taylor, Nived Viswanathan","doi":"10.33044/revuma.2921","DOIUrl":"https://doi.org/10.33044/revuma.2921","url":null,"abstract":". We address in this paper Fano manifolds with positive higher Chern characters, which are expected to enjoy stronger versions of several of the nice properties of Fano manifolds. For instance, they should be covered by higher dimensional rational varieties, and families of higher Fano manifolds over higher dimensional bases should admit meromorphic sections (modulo the Brauer obstruction). Aiming at finding new examples of higher Fano manifolds, we investigate positivity of higher Chern characters of rational homogeneous spaces. We determine which rational homogeneous spaces of Picard rank 1 have positive second Chern character, and show that the only rational homogeneous spaces of Picard rank 1 having positive second and third Chern characters are projective spaces and quadric hypersurfaces. We also classify Fano manifolds of large index having positive second and third Chern characters. We conclude by discussing conjectural characterizations of projective spaces and complete intersections in terms of these higher Fano conditions.","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41784769","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}
. Let F be a product preserving gauge bundle functor on double vector bundles. We introduce the complete lifting F ϕ : FK → ∧ p T ∗ FM ⊗ TFK of a double-linear semi-basic tangent valued p -form ϕ : K → ∧ p T ∗ M ⊗ TK on a double vector bundle K with base M . We prove that this com- plete lifting preserves the Frolicher–Nijenhuis bracket. We apply the results obtained to double-linear connections.
{"title":"Complete lifting of double-linear semi-basic tangent valued forms to Weil like functors on double vector bundles","authors":"W. Mikulski","doi":"10.33044/revuma.1619","DOIUrl":"https://doi.org/10.33044/revuma.1619","url":null,"abstract":". Let F be a product preserving gauge bundle functor on double vector bundles. We introduce the complete lifting F ϕ : FK → ∧ p T ∗ FM ⊗ TFK of a double-linear semi-basic tangent valued p -form ϕ : K → ∧ p T ∗ M ⊗ TK on a double vector bundle K with base M . We prove that this com- plete lifting preserves the Frolicher–Nijenhuis bracket. We apply the results obtained to double-linear connections.","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42794716","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}
{"title":"A convergence theorem for approximating minimization and fixed point problems for non-self mappings in Hadamard spaces","authors":"K. O. Aremu, C. Izuchukwu, O. Oyewole, O. Mewomo","doi":"10.33044/revuma.1762","DOIUrl":"https://doi.org/10.33044/revuma.1762","url":null,"abstract":"","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49657647","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}
. Let S = ( G,σ ) be a signed graph of order n and size m and let t 1 ,t 2 ,...,t n be the eigenvalues of S . The energy of S is defined as E ( S ) = P n j =1 | t j | . A connected signed graph is said to be unicyclic if its order and size are the same. In this paper we characterize, up to switching, the unicyclic signed graphs with first 11 minimal energies for all n ≥ 11. For 3 ≤ n ≤ 7, we provide complete orderings of unicyclic signed graphs with respect to energy. For 8 ≤ n ≤ 10, we determine unicyclic signed graphs with first 13 minimal energies.
． 设S = (G，σ)是一个n阶、大小为m的有符号图，设t1, t2，…n是S的特征值。S的能量定义为E (S) = P n j =1 | t j |。如果连通的有符号图的阶数和大小相同，则称其为单环图。本文刻画了n≥11时具有前11极小能量的单环符号图，直至交换。对于3≤n≤7，给出了单环符号图关于能量的完全序。对于8≤n≤10，我们确定了具有前13个最小能量的单环符号图。
{"title":"Ordering of minimal energies in unicyclic signed graphs","authors":"Tahir Shamsher, M. Bhat, S. Pirzada, Y. Shang","doi":"10.33044/REVUMA.2565","DOIUrl":"https://doi.org/10.33044/REVUMA.2565","url":null,"abstract":". Let S = ( G,σ ) be a signed graph of order n and size m and let t 1 ,t 2 ,...,t n be the eigenvalues of S . The energy of S is defined as E ( S ) = P n j =1 | t j | . A connected signed graph is said to be unicyclic if its order and size are the same. In this paper we characterize, up to switching, the unicyclic signed graphs with first 11 minimal energies for all n ≥ 11. For 3 ≤ n ≤ 7, we provide complete orderings of unicyclic signed graphs with respect to energy. For 8 ≤ n ≤ 10, we determine unicyclic signed graphs with first 13 minimal energies.","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":"77 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75898165","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}
{"title":"Split exact sequences of finite MTL-chains","authors":"J. L. Castiglioni, W. J. Zuluaga Botero","doi":"10.33044/revuma.1787","DOIUrl":"https://doi.org/10.33044/revuma.1787","url":null,"abstract":"","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46271294","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}
{"title":"Multidimensional common fixed point theorems for multivalued mappings in dislocated metric spaces","authors":"Deepa Karichery, Shaini Pulickakunnel","doi":"10.33044/revuma.1403","DOIUrl":"https://doi.org/10.33044/revuma.1403","url":null,"abstract":"","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48663835","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}
The Ramsey number $r(H)$ of a graph $H$ is the minimum $n$ such that any two-coloring of the edges of the complete graph $K_n$ contains a monochromatic copy of $H$. The threshold Ramsey multiplicity $m(H)$ is then the minimum number of monochromatic copies of $H$ taken over all two-edge-colorings of $K_{r(H)}$. The study of this concept was first proposed by Harary and Prins almost fifty years ago. In a companion paper, the authors have shown that there is a positive constant $c$ such that the threshold Ramsey multiplicity for a path or even cycle with $k$ vertices is at least $(ck)^k$, which is tight up to the value of $c$. Here, using different methods, we show that the same result also holds for odd cycles with $k$ vertices.
{"title":"Threshold Ramsey multiplicity for odd cycles","authors":"D. Conlon, J. Fox, B. Sudakov, F. Wei","doi":"10.33044/revuma.2874","DOIUrl":"https://doi.org/10.33044/revuma.2874","url":null,"abstract":"The Ramsey number $r(H)$ of a graph $H$ is the minimum $n$ such that any two-coloring of the edges of the complete graph $K_n$ contains a monochromatic copy of $H$. The threshold Ramsey multiplicity $m(H)$ is then the minimum number of monochromatic copies of $H$ taken over all two-edge-colorings of $K_{r(H)}$. The study of this concept was first proposed by Harary and Prins almost fifty years ago. In a companion paper, the authors have shown that there is a positive constant $c$ such that the threshold Ramsey multiplicity for a path or even cycle with $k$ vertices is at least $(ck)^k$, which is tight up to the value of $c$. Here, using different methods, we show that the same result also holds for odd cycles with $k$ vertices.","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45431260","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}
C. Banderier, Carlos Alexis Gómez Ruiz, F. Luca, F. Pappalardi, Enrique Treviño
Let a, n be positive integers that are relatively prime. We say that a/n can be represented as an Egyptian fraction of length k if there exist positive integers m1, . . . ,mk such that a n = 1 m1 + · · ·+ 1 mk . Let Ak(n) be the number of solutions a to this equation. In this article, we give a formula for A2(p) and a parametrization for Egyptian fractions of length 3, which allows us to give bounds to A3(n), to fa(n) = #{(m1,m2,m3) : a n = 1 m1 + 1 m2 + 1 m3 }, and finally to F (n) = #{(a,m1,m2,m3) : a n = 1 m1 + 1 m2 + 1 m3 }.
{"title":"On Egyptian fractions of length 3","authors":"C. Banderier, Carlos Alexis Gómez Ruiz, F. Luca, F. Pappalardi, Enrique Treviño","doi":"10.33044/REVUMA.1798","DOIUrl":"https://doi.org/10.33044/REVUMA.1798","url":null,"abstract":"Let a, n be positive integers that are relatively prime. We say that a/n can be represented as an Egyptian fraction of length k if there exist positive integers m1, . . . ,mk such that a n = 1 m1 + · · ·+ 1 mk . Let Ak(n) be the number of solutions a to this equation. In this article, we give a formula for A2(p) and a parametrization for Egyptian fractions of length 3, which allows us to give bounds to A3(n), to fa(n) = #{(m1,m2,m3) : a n = 1 m1 + 1 m2 + 1 m3 }, and finally to F (n) = #{(a,m1,m2,m3) : a n = 1 m1 + 1 m2 + 1 m3 }.","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":"27 1","pages":"257-274"},"PeriodicalIF":0.5,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75117642","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}
. Recurrent curvature properties are considered on four-dimensional pseudo-Riemannian homogeneous manifolds with non-trivial isotropy, and also on some geometric manifolds.
． 研究了具有非平凡各向同性的四维伪黎曼齐次流形和一些几何流形的循环曲率性质。
{"title":"Recurrent curvature over four-dimensional homogeneous manifolds","authors":"Milad Bastami, A. Haji-Badali, A. Zaeim","doi":"10.33044/REVUMA.1740","DOIUrl":"https://doi.org/10.33044/REVUMA.1740","url":null,"abstract":". Recurrent curvature properties are considered on four-dimensional pseudo-Riemannian homogeneous manifolds with non-trivial isotropy, and also on some geometric manifolds.","PeriodicalId":54469,"journal":{"name":"Revista De La Union Matematica Argentina","volume":"44 1","pages":"243-255"},"PeriodicalIF":0.5,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79219562","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}
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