A sampling of lomdus / interesting tidbits from Rav Kornmehl's teshuvos: ( the numbers in parenthesis correspond to simanim in cheilek 2)
(2) Rav Kornmehl opines that a ba'al koreh must have in mind to be motzi the tzibur, which means that although m'dina d'gemara a katan can get an aliya, there would have to be a gadol reading on his behalf. This is contrary to the psak of R' Moshe Soloveitchik, who once dealt with the case of a ba'al koreh who declared he will not have in mind to be motzi anyone. R' M. Soloveitchik advised that the ba'al koreh's intent made no difference -- the chiyuv is on the tzibur to hear keri'ah, but the ba'al koreh is not motzi them in anything. (R' Yosef Engel in Tziyunim laTorah who suggests this issue may be a machlokes Rishonim.)
R' Kornmehl in this piece makes a great diyuk in the Rambam in passing, but then seems to just gloss over it. Rambam writes in Tefilah 12:1:
משה רבנו תיקן להן לישראל, שיהיו קורין בתורה ברבים בשבת ובשני ובחמישי בשחרית
Then in Halacha 3 the Rambam writes:
אין קורין בתורה בציבור, בפחות מעשרה אנשים גדולים ובני חורין
The Rambam switches from "korin b'rabim" in the first halacha to "korin... b'tzibur" later on. Why the switch in language and does it have any significance? I wonder if others deal with this point (no, I haven't had a chance to check the Frankel Rambam's index.)
(3) He suggests that tefilah on a d'oraysa level has no set time, no set text, and need not even be articulated (avodah sheb'lev) because it is a subcategory, or a kiyum of the mitzvah of emunah.
(6) Why do women say a bracha and perform certain mitzvos aseh she'hazeman gerama but not others? Rav Kornmehl writes that the difference between shofar, lulav, etc. and tefilin (to take a few examples) is that tefilin are tashmishei kedusha. Women do not engage in mitzvos from which they are exempt that involve using (and hence potentially desecrating) an article of kedusha. Apparently the minhag was for women not to fulfill the mitzvah of sukkah either, which Rav Kornmehl fits into his theory by referring to the gemara, "...Chal shem shamayim al ha'sukkah," that sukkah is invested with kedusha as well.
(7) He writes that "kol b'isha ervah" applies to the speaking voice as well. Ideally women should therefore not give a public address/lecture (though Rav Kornmehl admits that this l'chatchila advice will likely not be heeded). Interestingly, there is a kula in this teshuvah as well. He writes that neither shiras Devorah or the possibility of women leining megilah pose a kol isha problem because "b'avidtayhu tarid," the listeners are engrossed in listening to the text and cannot devote their attention to the voice of the speaker.
(13) R' Akiva Eiger (Shut, siman 8) famously distinguishes between misasek on Shabbos and misasek with respect to other issurim. In the former case, misasek does not count as a ma'aseh aveira; in the latter case misasek is a ma'aseh aviera, but the Torah does not punish the crime. Nafka minah: what if an eved was about to pull up a stalk of wheat that he thought was not connected to the ground, but which his master knew was connected -- does the master have to stop the eved because of the mitzvah of shevisas avdo? If misasek is a ma'aseh aveirah, albeit one that does not warrant any penalty, the eved must be stopped. If however misasek is not a ma'aseh aveira, then the master has no obligation to intervene.
Rav Kornmehl writes that every act of a minor on Shabbos is in effect an act of misasek, yet the Torah warns that we are not allowed to allow our children to be mechalel Shabbos. QED that one must intervene to stop any misasek. I'm not sure I understand the proof. There is a special gezeiras hakasuv, "L'hazhir gedolim al ha'ketanim," that applies uniquely to children.
Rav Kornmehl connects the discussion to a sugya those learning daf yomi will be familiar with (Menachos 37b-38). Ravina saw Mar bar Rav Ashi's tzitzis were torn and he was wearing them outside on Shabbos. The gemara has different versions of the story -- in one Ravina told Mar bar Rav Ashi of the problem so he would not desecrate Shabbos; in another, Ravina remained silent because they were walking in a karmilis and the issur would only be derabbanan. Rav Kornmehl just throws out a few mareh mekomos without spelling out fully what he means, but the direction of his thinking is clear. Mar bar Rav Ashi would have been a misasek in this case, as he was unaware that he was doing any issur. Whether or not Ravina should have alerted him to the problem depends on R' Akiva Eiger's safeik.
(18) According to those poskim that do not apply the rule of "ain shliach 'dvar aveira" by issurei derabbanan, what would be the din if I did an akira on an object and then handed it off to someone else to deposit elsewhere on Shabbos? Am I chayav for the issur of hotza'ah? Rav Kornmehl says not. He makes a nice distinction between hilchos Shabbos, where the issur is on the gavra, and other issurim, where the issur is on the effect being produced. Where the only concern is outcome, even an action performed by a shliach can generate a chiyuv. However, when it comes to hilchos Shabbos one is chayav only if one personally does a complete melacha.
Bl"n maybe more to come.