How to find finite topological spaces with given quotient-spaces

Autor: Simoes-Pereira, J. M. S.

Our main problem is to find finite topological spaces to within homeomorphism, given (also to within homeomorphism) the quotient-spaces obtained by identifying one point of the space with each one of the other points. In a previous version of this pa

Externí odkaz: http://arxiv.org/abs/1612.04187

A note on completing quasi-distance and distance matrices

Autor: Zhang Yulin, Costa A. Veloso da, Simões-Pereira J. M. S.

Publikováno v: Special Matrices, Vol 7, Iss 1, Pp 226-229 (2019)

We give a necessary and sufficient condition for the existence of a quasi-distance matrix where some positive off-diagonal entries have been prescribed. Moreover, we give an algorithm for obtaining such a matrix. We analyze also the case where distan

Externí odkaz: https://doaj.org/article/11adc68939d24f91906d28003254449d

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On Matroids on Edge Sets of Graphs with Connected Subgraphs as Circuits

Autor: Simões-Pereira, J. M. S.

Publikováno v: Proceedings of the American Mathematical Society, 1973 May 01. 38(3), 503-506.

Externí odkaz: https://www.jstor.org/stable/2038939

The tower matrix, an alternative to deal with distances and quasi-distances

Autor: yulin zhang, Da Costa, A. V., Simões-Pereira, J. M. S.

Publikováno v: Scopus-Elsevier
Repositório Científico de Acesso Aberto de Portugal
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP

To any given n × n matrix D, associate a so-called tower matrix T with n × n rows and n columns. This matrix T deserves attention because it gives more information than D: in fact, the tower matrix exhibits, not only the shortest length of the path

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=dedup_wf_001::0c2c3b32ce866bea439882190407dc2c
https://hdl.handle.net/1822/63138