A pro-l version of the congruence subgroup problem for mapping class groups of genus one.

Abstract Let l be a prime number. In the present paper, we discuss a pro-l version of the congruence subgroup problem for mapping class groups of genus one. Our main result is that the pro-2 version has an affirmative answer, but the pro- l version for l ≥ 11 has a negative answer. [ABSTRACT FROM AUTHOR]