Semilinear damped wave equation on a compact Lie group with a non-autonomous forcing term

In the present note, we consider a semilinear damped wave equation on a compact Lie group with a non-autonomous nonlinearity φ (t)|u|ᵖ φ ( t ) | u | p . We are interested in describing how the nonnegative time-dependent factor φ φ affects the global in time prolongability of a local solution. In particular, the summability of the function φ φ provides a criterion to distinguish between the blow-up in finite time and global existence of small data. Finally, we derive sharp lifespan estimates for local in time solutions when φ ∈ L¹([0,+∞ )) φ ∉ L 1 ( [ 0 , + ∞ ) ) and satisfies a certain scaling condition, that we named uniform upper scaling condition.