Ran

Is it permitted to recite liturgical poems (piyutim) and krovot during the Amidah prayer?

Piyutim are permitted during the Amidah as communal needs.

If one complete Chumash is intact without errors while the others have defects, may it be read from publicly?

If one Chumash is complete without errors, one may be lenient and read from that specific Chumash ev…

Does adding a small amount of valid oil to melted fat or fish entrails make it permitted to kindle with them?

For melted fat that has solidified (re-congealed), even adding valid oil does not permit kindling.

Should kiddush be recited in the synagogue on Shabbat and Yom Tov?

The enactment of synagogue kiddush is permanent and cannot be voided even when guests no longer eat …

May additional aliyot be added beyond the required number on Yom Tov?

On Yom Tov one may not add beyond the required number of aliyot.

Is there bishul achar bishul (recooking) for fully-cooked LIQUID food that has cooled completely?

No bishul achar bishul even for fully-cooled food. Same as Rambam and Rashba.

May the mohel return to cut leftover flesh (tzitzin) after completing the circumcision on Shabbat?

Even after withdrawing the hand from cutting, as long as one is engaged in periah, it is still consi…

Can non-Jewish houses count as the required exclusion (shiur) for a city eruv?

Non-Jewish houses can serve as the shiur (exclusion) for the city eruv.

If the validity of an eruv is in doubt (e.g., it is uncertain whether it existed at bein hashmashot), is it valid?

For eruv chatzerot, even a case of safek tehorah/temei'ah is valid without needing chazakah; this is…

Does the prohibition against holding objects during prayer apply only to the specific items listed in the Talmud (tefillin, sefer, full plate, knife, money, loaf) or to any object?

The prohibition applies only to items where dropping causes loss or harm.