Results 31 to 40 of about 339 (176)

On Quasisymmetric Mappings Between Ultrametric Spaces

p-Adic Numbers, Ultrametric Analysis and Applications, 2021
In 1980 P. Tukia and J. Väisälä in seminal paper [P. Tukia and J. Väisälä, Quasisymmetric embeddings of metric spaces, Ann. Acad. Sci. Fenn., Ser. A I, Math. 5, 97--114 (1980)] extended a concept of quasisymmetric mapping known from the theory of quasiconformal mappings to the case of general metric spaces.
Petrov, Evgeniy, Salimov, Ruslan
openaire   +2 more sources

Results on the Existence and Convergence of Best Proximity Points

Fixed Point Theory and Applications, 2010
We first consider a cyclic φ-contraction map on a reflexive Banach space X and provide a positive answer to a question raised by Al-Thagafi and Shahzad on the existence of best proximity points for cyclic φ-contraction maps in reflexive ...
Ali Abkar, Moosa Gabeleh
doaj   +2 more sources

Hyperstability of the k-Cubic Functional Equation in Non-Archimedean Banach Spaces

Journal of Mathematics, 2020
Using the fixed point approach, we investigate a general hyperstability results for the following k-cubic functional equations fkx+y+fkx−y=kfx+y+kfx−y+2kk2−1fx, where k is a fixed positive integer ≥2, in ultrametric Banach spaces.
Youssef Aribou, Mohamed Rossafi
doaj   +1 more source

Forbidden four cycle, star graphs and isometric embeddings

Pracì Mìžnarodnogo Geometričnogo Centru
We prove the necessary and sufficient conditions under which ultrametric spaces of arbitrary infinite cardinality admit isometric embeddings into ultrametric spaces generated by labeled star graphs.
Olga Rovenska, Oleksiy Dovgoshey
doaj   +1 more source

Concentrated vulnerabilities in bees: Diet specialists have smaller geographic ranges

Insect Conservation and Diversity, EarlyView.
Niche breadth theory predicts a positive association between range size and diet breadth, which could concentrate risk among specialists, but this is not well established for bees. Using global occurrence data (range size) and natural history collection‐derived pollen data (diet breadth), we compared these traits in 633 species from six families and ...
Charles N. Thrift, Thomas J. Wood, An Bui, Hillary S. Young, Katja C. Seltmann   +4 more
wiley   +1 more source

Morphological Semigroups and Scale-Spaces on Ultrametric Spaces [PDF]

, 2017
Ultrametric spaces are the natural mathematical structure to deal with data embedded into a hierarchical representation. This kind of representations is ubiquitous in morphological image processing, from pyramids of nested partitions to more abstract dendrograms from minimum spanning trees.
Jesús Angulo, Santiago Velasco-Forero
openaire   +1 more source

Modular Locally Constant Mappings in Vector Ultrametric Spaces

Abstract and Applied Analysis, 2011
We give some sufficient conditions for mappings defined on vector ultrametric spaces to be modular locally constant.
Kamal Fallahi, Kourosh Nourouzi
doaj   +1 more source

Cryptic diversity and recent diversification in the Pyrrhulina australis species complex (Characiformes, Lebiasinidae) revealed by mitochondrial DNA

Journal of Fish Biology, EarlyView.
Abstract Pyrrhulina australis Eigenmann & Kennedy, 1903, is widely distributed across the main hydrographic basins of South America. The taxonomic integrity of this species is nevertheless challenged by the lack of clear diagnostic characters, its marked geographic variation and the morphological overlap with its congeners. In this context, the present
Taina Barbosa De Souza, Daniela Cristina Ferreira, Hugmar Pains Da Silva, Carolina B. Machado, Claudio Oliveira, André L. Netto‐Ferreira, Paulo C. Venere   +6 more
wiley   +1 more source

Characterizations of Urysohn universal ultrametric spaces

Analysis and Geometry in Metric Spaces
In this article, using the existence of infinite equidistant subsets of closed balls, we first characterize the injectivity of ultrametric spaces for finite ultrametric spaces. This method also gives characterizations of the Urysohn universal ultrametric
Ishiki Yoshito
doaj   +1 more source

Frozen and Scorched: Genomic Signatures of Adaptive Divergence and Hibernation in the Living Fossil Dromiciops

Ecology and Evolution, Volume 16, Issue 8, August 2026.
We evaluated adaptation to torpor and hibernation in the genus Dromiciops by comparing it with both torpid and non‐torpid marsupials, and investigated divergent selection signals between its two species. For the ancestral node, we identified positive selection in the genes PFKFB2, LAMP3, OTX1, and RAPSN, alongside an enrichment of pathways potentially ...
Elisa Gonzalez‐Ugalde, Paula M. Avendaño, Julián F. Quintero‐Galvis, Eduardo J. Pizarro, Francisco A. Cubillos, Roberto F. Nespolo, Fabiola León, Juliana A. Vianna   +7 more
wiley   +1 more source