Feynman Diagram 3

Dressed three-point vertex $\Gamma^{(3)}_{k,abc}(p_1,p_2,p_3)$ joining the external fields $\varphi_a$, $\varphi_b$ and $\varphi_c$, with all three momenta flowing inward. The hatched blob marks the full momentum-dependent vertex of the effective action rather than the bare coupling, so it already carries every quantum correction generated down to the scale $k$.