Constraint propagation equations of the 3+1 decomposition of f(R) gravity

Understand

Theories of gravity other than general relativity (GR) can explain the observed cosmic acceleration without a cosmological constant.

• One such class of theories of gravity is f(R).
• Metric f(R) theories have been proven to be equivalent to Brans-Dicke (BD) scalar-tensor gravity without a kinetic term.
• Using this equivalence and a 3+1 decomposition of the theory it has been shown that metric f(R) gravity admits a well-posed initial value problem.