[Avodah] Yom Tov Sheni for Olim LeReget to the Beit Mikdash

[Zev Sero]

Micha Berger wrote:

> Also, it appears that R Bachayei can't presume we were given a particular
> algorithm. Because if we already used it since miSinai, how do we have
> mishnayos and gemaros that don't assume lo ad"u rosh? However, the Rambam
> says "cheshbon zeh" is miSinai, which he can because those shitos could
> have been for al pi re'iyah periods.

I don't think "cheshbon zeh" can mean the exact system with all its
rules, including "lo adu rosh".  The reason RH can't be on a Sunday
is to strengthen the minhag nevi'im of chibut aravah; therefore the
rule can't predate the minhag.

-- 
Zev Sero                      The trouble with socialism is that you
zev at sero.name                 eventually run out of other people’s money
                                                     - Margaret Thatcher