2003 年 57 巻 2 号 p. 255-263
Scattering theory is studied for small solutions of nonlinear Klein-Gordon equations in a wider Hilbert space Σ*. The nonlinearities are power-type, the order of which is less than the conformal index but more than the Strauss index. The solutions are continuous on R to Σ* and the Σ*-norm tends to zero as t →±∞. The scattering operator acts on space-time functions.