  Starting from the primal principle based on the noncommutative nature of
(9+1)-dimensional spacetime, we construct a topologically twisted version of
the supersymmetric reduced model with a certain modification. Our formulation
automatically provides extra 1+1 dimensions, thereby the dimensions of
spacetime are promoted to 10+2. With a suitable gauge choice, we can reduce the
model with (10+2)-dimensional spacetime to the one with (9+1)-dimensions and
thus we regard this gauge as the light-cone gauge. It is suggested that the
model so obtained would describe the light-cone F-theory. From this viewpoint
we argue the relation of the reduced model to the matrix model of M-theory and
the SL(2,Z) symmetry of type IIB string theory. We also discuss the general
covariance of the matrix model in a broken phase, and make some comments on the
background independence.
