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[parent] ocr 2 proofreading test

(Definition)

necessary to consider the second bundle. The curvature form of our connection is a tensorial quadratic differential form in M, of type ad(G′) and with values in the Lie algebra L(G′) of G′. Since the Lie algebra L(G) of G is a subalgebra of L(G′), there is a natural projection of L(G′) into the quotient space L(G′)∕L(G). The image of the curvature form under this projection will be called the torsion form or the torsion tensor. If the forms πρ in (13) define a G-connection, the vanishing of the torsion form is expressed analytically by the conditions

        i′′
(22 )  cj′′k′′ = 0.

We proceed to derive the analytical formulas for the theory of a G-connection without torsion in the tangent bundle. In general we will consider such formulas in BG. The fact that the G-connection has no torsion simplifies (13) into the form

(23 )   dωi = Σρ,kaiρkπρ ∧ ωk.

By taking the exterior derivative of (23) and using (18), we get

            i  ρ    k
(24 )  Σ ρ,ka ρkΠ  ∧ ω   = 0,

where we put

                   1
(25)   Π ρ = dπρ + -Σ σ.τγσρτπ σ ∧ π τ.
                   2

For a fixed value of k we multiply the above equation by

 1             k−1      k+1          n
ω   ∧ .. . ∧  ω    ∧  ω    ... ∧  ω  ,

getting

∑
   aiρkΠ ρ ∧  ω1 ∧ . . . ∧ ωn  = 0,
 ρ

or

Σ ai Π ρ ≡ 0, mod  ωj.
 ρ ρk

Since the infinitesimal transformations Xρ are linearly independent, this implies that

  ρ            j
Π   ≡ 0, mod  ω .

It follows that Πρ is of the form

  ρ      ρ    j
Π  =  Σjϕj ∧ ω

where ϕjρ are Pfaffian forms. Substituting these expressions into (24), we get

Σ ρ,j,k(aiρkϕ ρj − aiρjϕρk) ∧ ωj ∧ ωk = 0.

It follows that

Σ (ai ϕ ρ− ai ϕρ) ≡ 0, mod  ωk.
 ρ  ρk  j   ρj k

Since G has the property (C), the above equations imply that

  ρ            k
ϕ j ≡ 0, mod  ω .

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Cross-references: formulas, tensor, Lie algebra, type

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Physics Classification: 00. (GENERAL)

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