Is it permissible for women to pray beside men in the mosque with a partition wall between them, or must they pray behind them?

If a woman prays in alignment with a man, and there is a barrier between them or a gap sufficient for one worshiper, the prayer is valid according to the majority of jurists. However, if she prays beside him without a barrier, the Hanafis have stipulated that this invalidates the prayer of three men (to her right, to her left, and behind her) under specific conditions, such as her being desirable, her entering into a prayer generally (not restricted to a specific type of prayer) with both sharing the same opening takbir and performance, and the Imam's intention to lead her. The majority of scholars, however, do not consider the prayer invalid in this case. The Sunnah is for women's rows to be behind men's rows.