Equivalent transformations of formulas in P_2 / A. B. Ugol’nikov. // Vestnik Moskovskogo Universiteta. Seriya 1. Matematika. Mekhanika. 2009. № 5. P. 0 [Moscow Univ. Math. Bulletin. Vol. 72, N 2, 2017. P. 202-208].

A new proof is given of the theorem originally proved by R.C. Lyndon that any equational class over a finite set of Boolean functions is finitely generated. The original proof of this theorem relied on E.L. Post's description of all closed classes of Boolean functions. J. Berman provided another proof of this theorem not based on description of Post's structure, but using some results from universal algebras.

Key words: formulas, identities, equivalent transformations.

№ 5/2009