Zobrazeno 1 - 10
of 172
pro vyhledávání: '"Geir Dahl"'
Autor:
Richard Brualdi, Geir Dahl
Publikováno v:
The Electronic Journal of Linear Algebra. 39:260-281
We introduce a generalization of alternating sign matrices (ASMs) called multiASMs and develop some of their properties. Classes of multiASMs with specified row and column sum vectors $R$ and $S$ extend the classes of $(0,1)$-matrices with specified
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::2872dd10fff2177758ee2e35926ee33a
https://doi.org/10.13001/ela.2023.7471
https://doi.org/10.13001/ela.2023.7471
Autor:
Richard A. Brualdi, Geir Dahl
Permutation graphs are graphs associated with permutations where edges represent inversions. We study different classes of permutation graphs and isomorphic permutation graphs. A complete answer of a basic isomorphism question is given for trees. A c
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5be5ed3c41b2c7cef840ebd739ae452a
http://hdl.handle.net/10852/99375
http://hdl.handle.net/10852/99375
Autor:
Geir Dahl, Richard A. Brualdi
Publikováno v:
Discrete Applied Mathematics. 297:21-34
We investigate ( 0 , 1 ) -matrices that are convex, which means that the ones are consecutive in every row and column. These matrices occur in discrete tomography. The notion of ranked essential sets, known for permutation matrices, is extended to co
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::baec35b2518dafa83e678ebc4f2b0f1a
https://doi.org/10.1016/j.dam.2021.02.038
https://doi.org/10.1016/j.dam.2021.02.038
The bottleneck matrix $M$ of a rooted tree $T$ is a combinatorial object encoding the spatial distribution of the vertices with respect to the root. The spectral radius of $M$, known as the Perron value of the rooted tree, is closely related to the t
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8f0ff0f199d6a92a29e34e82a6695f42
http://hdl.handle.net/10773/33404
http://hdl.handle.net/10773/33404
Autor:
Richard A. Brualdi, Geir Dahl
Publikováno v:
Discrete Applied Mathematics. 266:3-15
Let A be an n × n ( 0 , ∗ ) -matrix, so each entry is 0 or ∗ . An A -interval matrix is a ( 0 , 1 ) -matrix obtained from A by choosing some ∗ ’s so that in every interval of consecutive ∗ ’s, in a row or column of A , exactly one ∗ is
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::9026ab2d48f133a9226c6b1c2b64d062
https://doi.org/10.1016/j.dam.2018.03.024
https://doi.org/10.1016/j.dam.2018.03.024
Publikováno v:
Repositório Científico de Acesso Aberto de Portugal
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP
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Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1cb7fe17eaebd0b4e57bc792b51991b1
https://doi.org/10.1016/j.laa.2018.12.019
https://doi.org/10.1016/j.laa.2018.12.019
Autor:
Geir Dahl, Richard A. Brualdi
We study sign-restricted matrices (SRMs), a class of rectangular ( 0 , ± 1 ) -matrices generalizing the alternating sign matrices (ASMs). In an SRM each partial column sum, starting from row 1, equals 0 or 1, and each partial row sum, starting from
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c0bf99928b8f95ea77e790deed1269d4
http://arxiv.org/abs/2101.04150
http://arxiv.org/abs/2101.04150
Autor:
Geir Dahl, Richard A. Brualdi
Let $\Omega_n$ denote the class of $n \times n$ doubly stochastic matrices (each such matrix is entrywise nonnegative and every row and column sum is 1). We study the diagonals of matrices in $\Omega_n$. The main question is: which $A \in \Omega_n$ a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::024b8f3f61c82323fa1df87c5a75befa
http://arxiv.org/abs/2101.04143
http://arxiv.org/abs/2101.04143
Autor:
Richard A. Brualdi, Geir Dahl
Sign-restricted matrices (SRMs) are $(0, \pm 1)$-matrices where, ignoring 0's, the signs in each column alternate beginning with a $+1$ and all partial row sums are nonnegative. The most investigated of these matrices are the alternating sign matrice
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::08f84056a18373c52abcbbfc8d7a2db5
http://hdl.handle.net/10852/92770
http://hdl.handle.net/10852/92770