Does a lady have a Chiuv to eat on Erev Yom Kippur? The Shaagas Aryeh questions from one side it is a Mitzvas Asei Shehazman Grama and they should be Pottur. However they have a Chiuv to fast on Yom Kippur and maybe if you have to fast you also have to eat the day prior? The Shaagas Aryeh leaves it as a Tzoruch Iyun.
By Hilchos Tefilah, Tosafos are quoted in the famous controversy regarding whether women are obligated to daven. They say that the rule that women are from a time-bound, positive commandment only applies to mitzvos di'oraisa (commandments that the Torah itself directs us to do). Regarding Rabbinic Mitzvos this rule does not necessarily apply.