2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/191235After a brief review of the role three-nucleon forces play in the few-nucleon systems, the chiral-perturbation-theory approach to these forces is discussed. Construction of the (nominal) leading- and subleading-order Born terms and pion-rescattering graphs contributing to two-pion-exchange three-nucleon forces is reviewed, and comparisons are made of the types of such forces that are used today. It is demonstrated that the short-range $c$-term of the Tucson-Melbourne force is unnatural in terms of power counting and should be dropped. The class of two-pion-exchange three-nucleon forces then becomes rather uniform.14 pages, latex, 2 postscript figs. -- submitted to Phys. Rev. C -- epsfig.sty requiredNuclear Theorytext