5 papers
On the Unilateral Approximation Condition with Linear Arrays in Near-Field NLoS Propagation
Aniol MartÃ, Aniol Martí, Luca Sanguinetti +2
This paper investigates the validity of the unilateral approximation in near-field non-line-of-sight (NLoS) propagation for large-scale linear antenna arrays. Utilizing multiport c…
Poisson and Jacobi structures from 2-covariant tensors
Manuel de León, Xavier Grà cia, Rubén Izquierdo-López +2
Poisson and Jacobi structures play a fundamental role in the geometric description of many systems arising in classical mechanics. In most cases, the corresponding bivector field i…
Pairs of differential forms: a framework for precontact geometry
Xavier Grà cia, Ãngel MartÃnez-Muñoz, Xavier Rivas
Precontact manifolds extend contact geometry by weakening the maximal non-integrability condition of the defining -form. We clarify the geometric foundations of this structure b…
Time-dependent metrics and connections
Xavier Grà cia, Xavier Rivas, Daniel Torres
Time-dependent structures often appear in differential geometry, particularly in the study of non-autonomous differential equations on manifolds. One may study the geodesics associ…
The evolution operator connecting the Lagrangian and Hamiltonian formalisms for contact systems
Xavier Grà cia, Ãngel MartÃnez-Muñoz, Xavier Rivas +1
Some mechanical systems with dissipation can be described within the framework of the so-called contact mechanics: a modified form of the Euler-Lagrange equations stemming from Her…