532 research outputs found
On the minimal length of extremal rays for Fano 4-folds
The minimum of intersection numbers of the anti-canonical divisor with
rational curves on a Fano manifold is called pseudo-index. It is expected that
the intersection number of anti-canonical divisor attains to the minimum on an
extremal ray, i.e. there exists an extremal rational curve whose intersection
number with the anti-canonical divisor equals the pseudo-index. In this note,
we prove this for smooth Fano 4-folds having birational contractions.Comment: 10 page
Gauge invariant Lagrangian for non-Abelian tensor gauge fields of fourth rank
Using generalized field strength tensors for non-Abelian tensor gauge fields
one can explicitly construct all possible Lorentz invariant quadratic forms for
rank-4 non-Abelian tensor gauge fields and demonstrate that there exist only
two linear combinations of them which form a gauge invariant Lagrangian.
Together with the previous construction of independent gauge invariant forms
for rank-2 and rank-3 tensor gauge fields this construction proves the
uniqueness of early proposed general Lagrangian up to rank-4 tensor fields.
Expression for the coefficients of the general Lagrangian is presented in a
compact form.Comment: 27 pages, LaTex fil
Quantization of Neveu-Schwarz-Ramond Superstring Model in 10+2-dimensional Spacetime
We construct a Neveu-Schwarz-Ramond superstring model which is invariant
under supersymmetric U(1)_V * U(1)_A gauge transformations as well as the
super-general coordinate, the super local Lorentz and the super-Weyl
transformations on the string world-sheet. We quantize the superstring model by
covariant BRST formulation a la Batalin and Vilkovisky and noncovariant
light-cone gauge formulation. Upon the quantizations the model turns out to be
formulated consistently in 10+2-dimensional background spacetime involving two
time dimensions.Comment: 1+61 pages, no figures, LaTe
- …