We generalize to the case of Lie superalgebras the classical symplectic
double extension of symplectic Lie algebras introduced in [2]. We use this
concept to give an inductive description of nilpotent homogeneous-symplectic
Lie superalgebras. Several examples are included to show the existence of
homogeneous quadratic symplectic Lie superalgebras other than even-quadratic
even-symplectic considered in [6]. We study the structures of even (resp.
odd)-quadratic odd (resp.
The aim of this paper is to introduce and study quadratic Hom-Lie algebras,
which are Hom-Lie algebras with symmetric invariant nondegenerate bilinear
forms. We provide several constructions leading to examples and extend the
double extension theory to Hom-Lie algebras. We reduce the case where the twist
map is invertible to the study of involutive quadratic Lie algebras. We
establish a correspondence between the class of involutive quadratic Hom-Lie
algebras and quadratic simple Lie algebras with symmetric involution.
Centerless involutive quadratic Hom-Lie algebras are characterized.