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19992005
most citedA Li-type criterion for zero-free half-planes of Riemann's zeta function

2 citations · 2 across the 1 of their papers we have counts for

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math.CO2001

A Heawood-type result for the algebraic connectivity of graphs on surfaces

Pedro Freitas

We prove that the algebraic connectivity a(G) of a graph embedded on a nonplanar surface satisfies a Heawood-type result. More precisely, it is shown that the algebraic connectivit…

math.AP2001

Characterization of harmonic and subharmonic functions via mean-value properties

Pedro Freitas, Joao Palhoto Matos

We give a characterization of harmonic and subharmonic functions in terms of their mean values in balls and on spheres. This includes the converse of an inequality of Beardon's for…