Blowing-up solutions of Klein-Gordon equations with gauge variant semilinear terms in Friedmann-Lemaítre-Robertson-Walker spacetimes under finite speed of propagation

Blowing-up solutions of Klein-Gordon equations with gauge variant semilinear terms are considered in Friedmann-Lemaítre-Robertson-Walker spacetimes. Effects of spatial expansion or contraction on the solutions are studied through the scale-function and the curved mass.