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Ivancevic_Applied-Diff-Geom

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420 <strong>Applied</strong> <strong>Diff</strong>erential <strong>Geom</strong>etry: A Modern Introductionisomorphic functor Dual to the category • [so(n) i ] we get the dual category∗ •[so(n) ∗ i ] of cotangent, or, canonical Lie algebras so(n)∗ i (and theirhomomorphisms). To go directly from • [SO(n) i ] to ∗ •[so(n) ∗ i ] we use thecanonical functor Can. Therefore, we have a commutative triangle:Lie ✠•[so(n) i]• [SO(n) i ]❅❅❅❅❅❅❘CanLGA∼ =Dual A✲∗•[so(n) ∗ i ]Applying the functor Lie on the biodynamical configuration manifoldM, we get the product–tree of the same anthropomorphic structure, buthaving tangent Lie algebras so(n) i as vertices, instead of the groups SO(n) i .Again, applying the functor Can on M, we get the product–tree of the sameanthropomorphic structure, but this time having cotangent Lie algebrasso(n) ∗ i as vertices. Both the tangent algebras so(n) i and the cotangentalgebras so(n) ∗ i contain infinitesimal group generators: angular velocities˙q i = ˙q φ i – in the first case, and canonical angular momenta pi = p φi – in thesecond case [<strong>Ivancevic</strong> and Snoswell (2001)]. As Lie group generators, boththe angular velocities and the angular momenta satisfy the commutationrelations: [ ˙q φ i , ˙qψ i] = ɛφψθ˙q θi and [p φi , p ψi ] = ɛ θ φψ p θ i, respectively, wherethe structure constants ɛ φψθand ɛ θ φψconstitute the totally antisymmetricthird–order tensors.In this way, the functor Dual G : Lie ∼ = Can establishes the unique geometricalduality between kinematics of angular velocities ˙q i (involved inLagrangian formalism on the tangent bundle of M) and kinematics of angularmomenta p i (involved in Hamiltonian formalism on the cotangentbundle of M), which is analyzed below. In other words, we have two functors,Lie and Can, from the category of Lie groups (of which • [SO(n) i ] isa subcategory) into the category of (their) Lie algebras (of which • [so(n) i ]and ∗ •[so(n) ∗ i ] are subcategories), and a unique natural equivalence betweenthem defined by the functor Dual G . (As angular momenta p i are in a bijectivecorrespondence with angular velocities ˙q i , every component of thefunctor Dual G is invertible.) <strong>Geom</strong>etrical Proof. <strong>Geom</strong>etrical proof is given along the lines of Riemannianand symplectic geometry of mechanical systems, as follows (see 3.13.1

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