Authors: Guţul Ion
In article  the authors construct and classify all the hyperbolic space-forms Hn
/Gamma where Gamma is a torsion-free subgroup of minimal index in the congruence two subgroup Gamma2n
for n=3,4. In the present paper some hyperbolic 3- and 4-manifolds are constructed that are absent in .
Institute of Mathematics and Computer Science
cademy of Sciences of Moldova
5 Academiei str.,
Chisinau, MD-2028 Moldova