 To solve it, Pérez Capdevila introduced the concepts of overweight in adaptation, fuzzy coefficient for equal adequacy coefficients and adjusted tiebreaker coefficient for equal adequacy coefficients, which he defines with precision, to unpack in an indefinite number of cases with equal adequacy coefficients, thus rounding out a theory about the suitability of candidates for a preset profile

Built the operation of mixture of fuzzy sets, where from elements of different nature new elements are obtained with their certain degrees of belonging.In the field of applied mathematics he has achieved important advances regarding the evaluation of the economical effects and control of the exotic invading alien species, and he has accomplished important theoretical contributions.He has contributed to the concepts of individual benefit of an exotic invading alien species, collective benefit of an exotic invading alien species, a priori cost-benefit analysis of an exotic invading alien species, a posteriori cost-benefit analysis of an exotic invading alien species, as well as a method to accomplish those analyses.