The procedure of lumping analysis is developed for complex chemical re
actions. The number of ''lumping reactions'' of the contacted descript
ion equals the number of the independent routes in the sense of the Ho
riuti-Temkin theory of stationary reactions. An algorithm for obtainin
g the contracted description is illustrated by examples of the isomeri
zation reaction, hydrogenolysis of n-pentane on platinum and nickel, a
nd hydrogenation of iron carbide.