 Her results on Boolean formulas written in terms of formula_1, formula_2, and formula_3 were influential in the then nascent field of computational complexity theory.Subbotovskaya invented the method of random restrictions to Boolean functions.Starting with a function formula_4, a restriction formula_5 of formula_4 is a partial assignment to formula_7 of the formula_8 variables, giving a function formula_9 of fewer variables.