The Rabbinical prohibition of making a knot and the knots which are permitted to be tied and untied:
A. The Rabbinical definition of a permanent knot:
If one sets in his mind a designated time in which he will then certainly untie the knot, then even if this [designated time] is in a very long time [from now], it is not Biblically considered [a] permanent [knot] and he is [thus] exempt [from liability] whether upon tying it or untying it. However Rabinically this is also considered [a] permanent [knot] being that it is designated to last a certain amount of time and it is thus [Rabinically] forbidden to tie or untie.
Knots that are meant to be untied on the same day that they are made: However if it is not designated to last at all but rather to be untied the same day [that it was tied], such as knots of clothing and shoes of which when one places them on in the morning they are tied and when he removes them in the evening comes they are untied, then it is allowed to tie and untie it on Shabbos.
Torah Scholars who intend to not untie their shoes and clothes that night: However if one intends to not untie them that day, such as for example Torah Scholars that learn at night and do not remove their shoes and clothes at night, then it is forbidden for them to tie it on the morning of Shabbos if they intend to not untie them in the evening. Similarly it is forbidden to untie them on Shabbos if when he tied them on one of the days of the week he intended to not untie it immediately that coming night.
Tying their shoes and clothes on Shabbos without any intention: However if [the Torah Scholars] do not have any intention at all when they tie them, and rather they tie them casually, then they are allowed to tie them on Shabbos. [Furthermore] even if afterwards he [ends up] not untying it that night [and rather only unties it] after some time it is not considered due to this [even] a [Rabbinical] permanent knot being that at the time of tying it, it was not for certain that it would not be untied on the night after Shabbos, being that at times even the Torah Scholars remove their shoes at night prior to lying down.
Untying knots of cloths made without intention: Similarly it is allowed to untie it on Shabbos if one had tied it casually [without intention to leave overnight] even if it was tied a long time before Shabbos and was not untied in-between.
Knots that are always made to not be untied the next day: However knots that are always for certain left [tied] for a certain amount of time and it is never usual to untie it that same day, then it is forbidden to tie them on Shabbos even casually or to untie them.
Other Opinions: [However] there are opinions which say that any knot which is not made to last seven days is not considered a permanent knot even Rabinically and it is [thus] allowed to tie it and untie it on Shabbos. [Furthermore] even if most of the time it is common to tie it to last for seven days and only at times does one also untie it within seven days, such as for example a Torah Scholar which the majority of the time only removes his shoes and clothes from one Shabbos to the next Shabbos and it is thus found that their knots are left tied for seven days, although at times he does untie it within seven days, then it is not considered a permanent knot unless one has in mind while tying it to not untie it until after seven [days]. However when he casually ties them [without any intention] then it is not considered permanent unless it is common for him to always leave it [tied] for seven days, such as for example the strings used to tie the neck of a cloak, then for a person for whom it is never common to untie it [within 7 days] but rather only when he changes the cloak from Shabbos to Shabbos, then it is forbidden [for him] to tie it and untie it on Shabbos.
The Final Ruling: The final ruling is that one is to be stringent like the first opinion [to only allow to tie or untie a knot which is made to untie the day it is made] unless one is in great need [to tie or untie it], in which case one may be lenient to do so through a gentile.
B. May one make a professional knot to last one day or an amateur knot to last many days?
First Opinion– Rabbinical prohibition by amateur knots made to last even temporarily, and by all professional knots: It is Rabinically forbidden [to tie even amateur knots] even if it is not made to last forever but rather only for a set period of time as explained [above, meaning for more than one day according to the stringent opinion, and 7 days according to the lenient opinion]. However a knot which is done professionally, even if it not made to last at all but rather to be untied that same day, is Rabinically forbidden to tie or untie on Shabbos, due to a decree [that if this were to be allowed then one may come to make also] a professional knot that is meant to last forever of which one is Biblically liable on.
Second Opinion-No difference between a professional and amateur knot: There are other opinions that say there is no difference at all between a professionally made and amateur made [knots], as even on an amateur knot one is Biblically liable if made for it to permanently last, and if [a knot] is designated to not last at all [then] in a situation that it is [thus] allowed to make an amateur knot it is also allowed to make a professional knot.
The Final Ruling: One is to be strict like the I opinion [and it is thus forbidden to tie or untie professional knots in all cases].
C. Knots which are at times left permanently:
Any knot which at times one retracts his initial intentions and decides to nullify it there forever, then even if [one] now wants to make it without intent to nullify it there, it is forbidden [to make it] because he may change his mind and decide to nullify it there.
Tying a rope to a cow and its trough: Therefore it is forbidden to take a rope and tie [one end of] it to a trough and [the other end to] a cow, because perhaps when one will wish to remove the cow from there he will always untie only one of [the ropes] ends and leave the second [knot of the second end] there permanently and it will [thus] be a permanent knot.
Woven ropes: However this only refers to other [non-woven] ropes, however with a woven rope it is allowed [to tie it] being that one will not nullify it there. There is no decree made here against a woven rope due to [that one may come to use] other ropes being that even by other ropes it is not common that one will nullify one end to be there forever, and rather he will at times undo one end and at time the other end.
Tying the rope of a cow to its trough or vice versa: All the above is referring to tying a rope on Shabbos onto [both] the trough and the cow, however if it was already tied to the trough and one wants to tie it now to the cow or if it was tied to the cow and he now wants to tie it to the trough, then it is allowed to be done with any rope, as if he will come to nullify one of its knots to stay there permanently one can assume that the same knot which was already tied will [be the one that he will decide to nullify and] leave tied there forever.
 Mordechaiy, brought in Rama
 Brought in Taz 5, as is always the ruling regarding a Shevus Deshvus, that in a time of need one may be lenient. [Levushei Serud on Taz, as is explained in 307]. Vetzaruch Iyun as to what is the novelty here of stating this allowance if it is a general rule in all Rabbinical cases. Furthermore, it can be implied from here that only in a case that the knot is made to be undone within 7 days is it permitted in a case of need to ask a gentile. If however it is meant to be undone past 7 days then it would be forbidden to even ask a gentile. Vetzaruch Iyun as for what reason would this be any different than any other Rabbinical prohibition, which the rule is that one is allowed to do it through a gentile in times of need.
Perhaps however one can say that the above rule only applies by a new Rabbinical decree made against coming to do something else. However if it is a Rabbinical prohibition due to a redefinition of the Biblical law, as is the case here with regards to the definition of “permanent knot”, then it receives the same severity as does a Biblical prohibition, and may not be done through a gentile. [see Peri Megadim M”Z 317/5 which suggests a similar differentiation; This is also similar to Admur’s ruling in Hilchos Pesach of the Rabbinical prohibition of Baal Yerah, that the sages invalidated the Bittul, and thus consequently the prohibition of Baal Yerah remains] Thus accordingly, in a case that it is Rabbinically forbidden to make a knot according to all, which for more than 7 days, then it may not be undone at all through a gentile. Vetzaruch Iyun.
 This opinion is the same opinion mentioned above by the Biblical prohibition.
 This opinion is the same opinion mentioned above by the Biblical prohibition.
 Rosh, Rashi, Tur and Rama