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1
Content available remote Product preserving bundles on foliated manifolds
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EN
We present a complete description of all product preserving bundle functors on the category ℱol of all foliated manifolds and their leaf respecting maps in terms of homomorphisms of Weil algebras.
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Content available remote Product preserving gauge bundle functors on all principal bundle homomorphisms
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EN
Let 𝓟𝓑 be the category of principal bundles and principal bundle homomorphisms. We describe completely the product preserving gauge bundle functors (ppgb-functors) on 𝓟𝓑 and their natural transformations in terms of the so-called admissible triples and their morphisms. Then we deduce that any ppgb-functor on 𝓟𝓑 admits a prolongation of principal connections to general ones. We also prove a "reduction" theorem for prolongations of principal connections into principal ones by means of Weil functors. We observe that there exist plenty of such prolongations. In Appendix, we classify the natural operators lifting vector-valued 1-forms (or vector-valued maps) to vector-valued 1-forms on Weil bundles.
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Content available remote On prolongation of connections
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Let Y → M be a fibred manifold with m-dimensional base and n-dimensional fibres. Let r, m,n be positive integers. We present a construction $B^r$ of rth order holonomic connections $B^r(Γ,∇):Y → J^rY$ on Y → M from general connections Γ:Y → J¹Y on Y → M by means of torsion free classical linear connections ∇ on M. Then we prove that any construction B of rth order holonomic connections $B(Γ,∇):Y → J^rY$ on Y → M from general connections Γ:Y → J¹Y on Y → M by means of torsion free classical linear connections ∇ on M is equal to $B^r$. Applying $B^r$, for any bundle functor $F:ℱℳ_{m,n} →ℱℳ$ on fibred (m,n)-manifolds we present a construction $ℱ^r_q$ of rth order holonomic connections $ℱ^r_q(Θ,∇):FY → J^r(FY)$ on FY → M from qth order holonomic connections $Θ:Y → J^qY$ on Y → M by means of torsion free classical linear connections ∇ on M (for q=r=1 we have a well-known classical construction ℱ(Γ,∇):FY → J¹(FY)). Applying $B^r$ we also construct a so-called (Γ,∇)-lift of a wider class of geometric objects. In Appendix, we present a direct proof of a (recent) result saying that for r ≥ 3 and m ≥ 2 there is no construction A of rth order holonomic connections $A(Γ):Y → J^rY$ on Y → M from general connections Γ:Y → J¹Y on Y → M.
EN
All natural operators A transforming a linear vector field X on a vector bundle E into a vector field A(X) on the r-jet prolongation $J^rE$ of E are given. Similar results are deduced for the r-jet prolongations $J^r_{v}E$ and $J^{[r]}E$ in place of $J^rE$.
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Content available remote On the fiber product preserving gauge bundle functors on vector bundles
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We present a complete description of all fiber product preserving gauge bundle functors F on the category $𝓥𝓑_m$ of vector bundles with m-dimensional bases and vector bundle maps with local diffeomorphisms as base maps. Some corollaries of this result are presented.
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Content available remote Product preserving gauge bundle functors on vector bundles
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A complete description is given of all product preserving gauge bundle functors F on vector bundles in terms of pairs (A,V) consisting of a Weil algebra A and an A-module V with $dim_{ℝ}(V) < ∞$. Some applications of this result are presented.
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Content available remote Continuity of projections of natural bundles
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This paper is a contribution to the axiomatic approach to geometric objects. A collection of a manifold M, a topological space N, a group homomorphism E: Diff(M) → Homeo(N) and a function π: N → M is called a quasi-natural bundle if (1) π ∘ E(f) = f ∘ π for every f ∈ Diff(M) and (2) if f,g ∈ Diff(M) are two diffeomorphisms such that f|U = g|U for some open subset U of M, then E(f)|π^{-1}(U) = E(g)|π^{-1}(U). We give conditions which ensure that π: N → M is continuous. In particular, if (M,N,E,π) is a quasi-natural bundle with N Hausdorff, then π is continuous. Using this result, we classify (quasi) prolongation functors with compact fibres.
8
Content available remote Lifting distributions to the cotangent bundle
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A classification of all $ℳ f_m$-natural operators $A: Gr_p ⟿ Gr_qT*$ lifting p-dimensional distributions D ⊂ TM on m-manifolds M to q-dimensional distributions A(D) ⊂ TT*M on the cotangent bundle T*M is given.
9
Content available remote On "special" fibred coordinates for general and classical connections
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Using a general connection Γ on a fibred manifold p:Y → M and a torsion free classical linear connection ∇ on M, we distinguish some "special" fibred coordinate systems on Y, and then we construct a general connection $\widetilde{ℱ}(Γ,∇)$ on Fp:FY → FM for any vector bundle functor F: ℳ f → 𝓥𝓑 of finite order.
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Content available remote The natural operators $T^{(0,0)} ⇝ T^{(1,1)}T^{(r)}$
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We study the problem of how a map f:M → ℝ on an n-manifold M induces canonically an affinor $A(f): TT^{(r)}M → TT^{(r)}M$ on the vector r-tangent bundle $T^{(r)}M = (J^r(M,ℝ)₀)*$ over M. This problem is reflected in the concept of natural operators $A:T^{(0,0)}_{|ℳ fₙ} ⇝ T^{(1,1)}T^{(r)}$. For integers r ≥ 1 and n ≥ 2 we prove that the space of all such operators is a free (r+1)²-dimensional module over $𝓒^{∞}(T^{(r)}ℝ)$ and we construct explicitly a basis of this module.
11
Content available remote Liftings of 1-forms to $(J^{r}T*)*$
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Let $J^{r}T*M$ be the r-jet prolongation of the cotangent bundle of an n-dimensional manifold M and let $(J^{r}T*M)*$ be the dual vector bundle. For natural numbers r and n, a complete classification of all linear natural operators lifting 1-forms from M to 1-forms on $(J^{r}T*M)*$ is given.
12
Content available remote On prolongations of projectable connections
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We extend the concept of r-order connections on fibred manifolds to the one of (r,s,q)-order projectable connections on fibred-fibred manifolds, where r,s,q are arbitrary non-negative integers with s ≥ r ≤ q. Similarly to the fibred manifold case, given a bundle functor F of order r on (m₁,m₂,n₁,n₂)-dimensional fibred-fibred manifolds Y → M, we construct a general connection ℱ(Γ,Λ):FY → J¹FY on FY → M from a projectable general (i.e. (1,1,1)-order) connection $Γ:Y → J^{1,1,1}Y$ on Y → M by means of an (r,r,r)-order projectable linear connection $Λ:TM → J^{r,r,r}TM$ on M. In particular, for $F = J^{1,1,1}$ we construct a general connection $𝒥^{1,1,1}(Γ,∇): J^{1,1,1}Y → J¹J^{1,1,1}Y$ on $J^{1,1,1}Y → M$ from a projectable general connection Γ on Y → M by means of a torsion-free projectable classical linear connection ∇ on M. Next, we observe that the curvature of Γ can be considered as $𝓡_Γ:J^{1,1,1}Y → T*M ⊗ VJ^{1,1,1}Y$. The main result is that if m₁ ≥ 2 and n₂ ≥ 1, then all general connections $D(Γ,∇):J^{1,1,1}Y → J¹J^{1,1,1}Y$ on $J^{1,1,1}Y → M$ canonically depending on Γ and ∇ form the one-parameter family $𝒥^{1,1,1}(Γ,∇) + t𝓡_Γ$, t ∈ ℝ. A similar classification of all general connections D(Γ,∇):J¹Y → J¹J¹Y on J¹Y → M from (Γ,∇) is presented.
13
Content available remote Gauge natural prolongation of connections
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The main result is the classification of all gauge bundle functors H on the category $𝓟ℬ_m(G)$ which admit gauge natural operators transforming principal connections on P → M into general connections on HP → M. We also describe all gauge natural operators of this type. Similar problems are solved for the prolongation of principal connections to HP → P. A special attention is paid to linear connections.
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Content available remote On prolongation of higher order connections
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We describe all bundle functors G admitting natural operators transforming rth order holonomic connections on a fibered manifold Y → M into rth order holonomic connections on GY → M. For second order holonomic connections we classify all such natural operators.
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Content available remote On lifting of connections to Weil bundles
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We prove that the problem of finding all $ℳ f_m$-natural operators $B:Q⟿ QT^A$ lifting classical linear connections ∇ on m-manifolds M to classical linear connections $B_M(∇)$ on the Weil bundle $T^{A}M$ corresponding to a p-dimensional (over ℝ) Weil algebra A is equivalent to the one of finding all $ℳ f_m$-natural operators $C:Q ⟿ (T¹_{p-1},T* ⊗ T* ⊗ T)$ transforming classical linear connections ∇ on m-manifolds M into base-preserving fibred maps $C_M(∇):T¹_{p-1}M = ⨁^{p-1}_{M} TM → T*M ⊗ T*M ⊗ TM$.
16
Content available remote On involutions of iterated bundle functors
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We introduce the concept of an involution of iterated bundle functors. Then we study the problem of the existence of an involution for bundle functors defined on the category of fibered manifolds with m-dimensional bases and of fibered manifold morphisms covering local diffeomorphisms. We also apply our results to prolongation of connections.
17
Content available remote Product preserving bundle functors on fibered fibered manifolds
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We investigate the category of product preserving bundle functors defined on the category of fibered fibered manifolds. We show a bijective correspondence between this category and a certain category of commutative diagrams on product preserving bundle functors defined on the category ℳ f of smooth manifolds. By an application of the theory of Weil functors, the latter category is considered as a category of commutative diagrams on Weil algebras. We also mention the relation with natural transformations between product preserving bundle functors on the category of fibered manifolds.
18
Content available remote Non-existence of exchange transformations of iterated jet functors
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We study the problem of the non-existence of natural transformations $J^{r}J^{s}Y → J^{s}J^{r}Y$ of iterated jet functors depending on some geometric object on the base of Y.
19
Content available remote On infinitesimal automorphisms of foliated manifolds
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Let F:ℱol → ℱℳ be a product preserving bundle functor on the category ℱol of foliated manifolds (M,ℱ) without singularities and leaf respecting maps. We describe all natural operators C transforming infinitesimal automorphisms X ∈ 𝒳(M,ℱ) of foliated manifolds (M,ℱ) into vector fields C(X)∈ 𝒳(F(M,ℱ)) on F(M,ℱ).
20
Content available remote Gauge natural constructions on higher order principal prolongations
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Let $W^r_mP$ be a principal prolongation of a principal bundle P → M. We classify all gauge natural operators transforming principal connections on P → M and rth order linear connections on M into general connections on $W^r_mP → M$. We also describe all geometric constructions of classical linear connections on $W^r_mP$ from principal connections on P → M and rth order linear connections on M.
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