The paper presents a comprehensive analysis of the Wilkinson Microwave Anisotropy Probe (WMAP) data, combining it with small-scale cosmic microwave background (CMB) measurements and large-scale structure data to test inflationary models. The WMAP data reveal a large-angle anti-correlation in the temperature-polarization cross-power spectrum, indicating adiabatic superhorizon fluctuations at the time of decoupling. The data are consistent with pure adiabatic fluctuations, ruling out a correlated CDM isocurvature component. Using WMAP constraints on the scalar power spectrum and the amplitude of gravity waves, the authors explore the parameter space of inflationary models. They find that a minimally-coupled $\lambda \phi^4$ model is disfavored at more than 3$\sigma$ when combined with smaller-scale CMB and large-scale structure data. The primordial parameters derived from WMAP data alone are: $n_s = 1.20^{+0.12}_{-0.11}$, $dn_s/d\ln k = -0.077^{+0.050}_{-0.052}$, $A(k_0 = 0.002 \ \text{Mpc}^{-1}) = 0.71^{+0.10}_{-0.11}$, and $r(k_0 = 0.002 \ \text{Mpc}^{-1}) < 1.28$. The paper also discusses the implications of these findings for different inflationary models, including single-field and double-field models, and examines the evidence for features in the inflaton potential.The paper presents a comprehensive analysis of the Wilkinson Microwave Anisotropy Probe (WMAP) data, combining it with small-scale cosmic microwave background (CMB) measurements and large-scale structure data to test inflationary models. The WMAP data reveal a large-angle anti-correlation in the temperature-polarization cross-power spectrum, indicating adiabatic superhorizon fluctuations at the time of decoupling. The data are consistent with pure adiabatic fluctuations, ruling out a correlated CDM isocurvature component. Using WMAP constraints on the scalar power spectrum and the amplitude of gravity waves, the authors explore the parameter space of inflationary models. They find that a minimally-coupled $\lambda \phi^4$ model is disfavored at more than 3$\sigma$ when combined with smaller-scale CMB and large-scale structure data. The primordial parameters derived from WMAP data alone are: $n_s = 1.20^{+0.12}_{-0.11}$, $dn_s/d\ln k = -0.077^{+0.050}_{-0.052}$, $A(k_0 = 0.002 \ \text{Mpc}^{-1}) = 0.71^{+0.10}_{-0.11}$, and $r(k_0 = 0.002 \ \text{Mpc}^{-1}) < 1.28$. The paper also discusses the implications of these findings for different inflationary models, including single-field and double-field models, and examines the evidence for features in the inflaton potential.