Automorphism groups of P1$\mathbb {P}^1$‐bundles over geometrically ruled surfaces
Abstract We classify the pairs (X,π)$(X,\pi)$, where π:X→S$\pi \colon X\rightarrow S$ is a P1$\mathbb {P}^1$‐bundle over a non‐rational geometrically ruled surface S$S$ and Aut∘(X)$\mathrm{Aut}^\circ (X)$ is relatively maximal, that is, maximal with respect to the inclusion in the group Bir(X/S)$\mathrm{Bir}(X/S)$.
Pascal Fong
wiley +1 more source
Isotopy and equivalence of knots in 3‐manifolds
Abstract Two knots K$K$ and J$J$ in S3$S^3$ are isotopic if and only if they are related by an orientation‐preserving diffeomorphism of S3$S^3$. This claim follows from the fact that any orientation‐preserving self‐diffeomorphism of S3$S^3$ is isotopic to the identity. We show that this same idea applies to any prime oriented closed 3‐manifold.
Paolo Aceto +4 more
wiley +1 more source
Low-Complexity Propagator Based Two Dimensional Angle Estimation for Coprime MIMO Radar
The problem of 2-D angle estimation for coprime multiple-input multiple-output (MIMO) radar is considered, and a low-complexity propagator based method is proposed.
Jianfeng Li, Defu Jiang
doaj +1 more source
Motivic mirror symmetry and χ$\chi$‐independence for Higgs bundles in arbitrary characteristic
Abstract We prove that the (twisted orbifold) motives of the moduli spaces of SLn$\mathrm{SL}_n$ and PGLn$\mathrm{PGL}_n$‐Higgs bundles of coprime rank and degree on a smooth projective curve over an algebraically closed field in which the rank is invertible are isomorphic in Voevodsky's triangulated category of motives.
Victoria Hoskins, Simon Pepin Lehalleur
wiley +1 more source
Underdetermined Direction-of-Arrival Estimation with Coprime Array via Atomic Norm Minimization [PDF]
The coprime array provides the possibility of resolving more signals than the sensors for the direction-of-arrival (DOA) estimation application. However, the non-consecution of its virtual array raises challenges for making full use of the degree of ...
Y. Pan +4 more
doaj
2-D DOA estimation method based on coprime array MIMO radar
Aiming at the problem that traditional direction of arrival (DOA) estimation methods cannot handle multiple sources with high accuracy while increasing the degrees of freedom (DOF), a new method for 2-D DOA estimation based on coprime array MIMO radar ...
Fei Zhang +4 more
doaj +1 more source
The fundamental group of the complement of a generic fiber‐type curve
Abstract In this paper, we describe and characterize the fundamental group of the complement of generic fiber‐type curves, that is, unions of (the closure of) finitely many generic fibers of a component‐free pencil F=[f:g]:CP2⤍CP1$F=[f:g]:\mathbb {C}\mathbb {P}^2\dashrightarrow \mathbb {C}\mathbb {P}^1$.
José I. Cogolludo‐Agustín +1 more
wiley +1 more source
Delay Coprime Array: A New Sparse Linear Array for Fast and Robust DOA Estimation [PDF]
In this letter, we propose a new sparse linear array (SLA), termed delay coprime array (DCA), and correspondingly develop a low-complexity direction of arrival (DOA) estimation algorithm.
Xiao, M +4 more
core +1 more source
Direction of Arrival Estimation Using Augmentation of Coprime Arrays [PDF]
Recently, direction of arrival (DOA) estimation premised on the sparse arrays interpolation approaches, such as co-prime arrays (CPA) and nested array, have attained extensive attention because of the effectiveness and capability of providing higher degrees of freedom (DOFs). The co-prime array interpolation approach can detect O(MN) paths with O(M + N)
Tehseen Ul Hassan +3 more
openaire +2 more sources
Presentations of the braid group of the complex reflection group G(d,d,n)$G(d,d,n)$
Abstract We show that the braid group associated to the complex reflection group G(d,d,n)$G(d,d,n)$ is an index d$d$ subgroup of the braid group of the orbifold quotient of the complex numbers by a cyclic group of order d$d$. We also give a compatible presentation of G(d,d,n)$G(d,d,n)$ and its braid group for each tagged triangulation of the disk with ...
Francesca Fedele, Bethany Rose Marsh
wiley +1 more source

