Adopting the pullback approach to Finsler geometry, the aim of the present paper is to provide new intrinsic (coordinate-free) proofs of intrinsic versions of the existence and uniqueness theorems for the Cartan and Berwald connections on a Finsler manifold. To accomplish this, the notions of semispray and nonlinear connection associated with a given regular connection, in the pullback bundle, ...

The aim of the present paper is to provide an intrinsic investigation of the fundamental properties of the most important geometric objects associated with the fundamental linear connections on a Finsler manifold. We introduce and investigate intrinsically the most general properties concerning the torsion tensor fields and the curvature tensor fields associated with a certain regular connectio...

The product of safe Petri nets is a well known operation : it generalizes to concurrent systems the usual synchronous product of automata. In this paper, we consider a more general way of combining nets, called a pullback. The pullback operation generalizes the product to nets which interact both by synchronized transitions and/or by a shared sub-net (i.e. shared places and transitions). To obt...

This study, in a broad sense, fills in the missing parts in previous efforts at pullback stripping mode design with a dipping coal seam. Three different spoiling procedures have been developed: the normal mode, where the coal seam is flat/nearly flat; the uphill mode, where the coal seam is dipping and the dragline spoils uphill; and the downhill mode, where the coal seam is again dipping but t...

Let R ∗ = R2k+1 \ {~0} (k ≥ 1) and π: R ∗ → S2k be the map sending ~r ∈ R ∗ to ~r |~r| ∈ S 2k . Denote by P → R ∗ the pullback by π of the canonical principal SO(2k)-bundle SO(2k + 1) → S2k . Let E] → R ∗ be the associated co-adjoint bundle and E] → T ∗R ∗ be the pullback bundle under projection map T ∗R ∗ → R ∗ . The canonical connection on SO(2k + 1) → S2k turns E] into a Poisson manifold. Th...

Fix a smooth very ample curve C on a K3 or abelian surface X . Let M denote the moduli space of pairs of the form (F, s), where F is a stable sheaf over X whose Hilbert polynomial coincides with that of the direct image, by the inclusion map of C in X , of a line bundle of degree d over C, and s is a nonzero section of F . Assume d to be sufficiently large such that F has a nonzero section. The...

Non-perturbative instanton corrections to the moduli space geometry of type IIA string theory compactified on a Calabi-Yau space are derived and found to contain order e−1/gs contributions, where gs is the string coupling. The computation reduces to a weighted sum of supersymmetric extremal maps of strings, membranes and fivebranes into the Calabi-Yau space, all three of which enter on equal fo...

Security problems in collaborative work between multiple agencies are less well understood than those in the business and defence worlds. We develop a perspective for policies and models that is task-based on a need-toknow basis. These policies are represented by two protocols, the first CTCP (Collaboration Task-based Creation Protocol) dealing with negotiation, decision and agreement between t...