Test ofKl3Soft-Pion Theorem and Chiral SW(3) Model

An exact inequality involving the $K_{l3\mathrm{}}$ scalar form factor $D\left(t\right)\mathrm{}$ and its derivatives is derived by utilizing the soft-pion theorem. From our analysis, the chiral SW(3) model of Gell-Mann, Oakes, and Renner and of Glashow and Weinberg appears to be inconsistent with the present experimental data. The linear extrapolation method for $D\left(t\right)\mathrm{}$ is also shown to lead to an inconsistent result.