On the well formulation of the Initial Value Problem of metric--affine $f(R)$-gravity

Understand

We study the well formulation of the initial value problem of f(R)-gravity in the metric-affine formalism.

• The problem is discussed in vacuo and in presence of perfect-fluid matter, Klein-Gordon and Yang-Mills fields.
• Adopting Gaussian normal coordinates, it can be shown that the problem is always well-formulated.
• Our results refute some criticisms to the viability of f(R)-gravity recently appeared in literature.