12.07.2015 Views

Ivancevic_Applied-Diff-Geom

Ivancevic_Applied-Diff-Geom

Ivancevic_Applied-Diff-Geom

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

<strong>Applied</strong> Bundle <strong>Geom</strong>etry 667It is a basic fact in algebra that the Clifford algebra is the unique (upto isomorphism) solution to the following universal problem.If A is an algebra and c : V −→ A is a linear map satisfyingc(v 2 )c(v 1 ) + c(v 1 )c(v 2 ) = −2Q(v 1 , v 2 ), (for all v 1 , v 2 ∈ V ),then there is a unique algebra homomorphism from C(V, Q) to A extendingthe map c.The Clifford algebra may be realized as the quotient T (V )/I Q whereT (V ) =∞⊕T k (V )k=1is the tensor algebra of V with T k (V ) generated byand I Q is generated by{ v 1 ⊗ v 2 ⊗ · · · ⊗ v k | v 1 , v 2 , . . . , v k ∈ V }{v 1 ⊗ v 2 + v 2 ⊗ v 1 + 2Q(v 1 , v 2 ) | v 1 , v 2 ∈ V }The tensor algebra T (V ) has a Z 2 −grading obtained from the naturalN−grading after reduction mod 2:T (V ) = T + (V ) + T − (V ),whereT + (V ) = R ⊕ T 2 (V ) ⊕ T 4 (V ) ⊕ · · · ⊕ T 2k (V ) ⊕ . . . ,T − (V ) = V ⊕ T 3 (V ) ⊕ T 5 (V ) ⊕ · · · ⊕ T 2k+1 (V ) ⊕ . . .Therefore it forms a super–algebra.Similarly, for k = 0, 1, 2, 3, . . . , letC k (V ) = T k (V )/I Q ,and letC + (V ) = R ⊕ C 2 (V ) ⊕ C 4 (V ) ⊕ · · · ⊕ C 2k (V ) ⊕ . . . ,C − (V ) = V ⊕ C 3 (V ) ⊕ C 5 (V ) ⊕ · · · ⊕ C 2k+1 (V ) ⊕ . . .Since the ideal I Q is generated by elements from the evenly gradedsubalgebra T + (V ), C(V ) is itself a superalgebra and we have the gradingC(V ) = C + (V ) + C − (V ).Let E be a module over R or C which is Z 2 −graded,E = E + ⊕ E − .

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!