Title: I. Chajda - Deductive systems in universal algebra

Abstract: We generalize the concept of deductive system of Hilbert algebras
to the general case in weakly regular varieties of algebras. We show that
congruence kernels of algebras in such a variety (alias ideals) coincide
with these deductive systems. Moreover, a similar construction can be used
for a description of congruence classes in algebras of a regular variety
which is efficient (in a polynomial time) whenever an algebra is finite and
of a finite type.