...
...
When a person sells an item to a colleague by measure, by weight or by number, and errs to the slightest degree, the colleague may seek redress at any time.
The principles of ona'ah apply only with regard to an object's value. An error in calculation, by contrast, is always reason to seek redress.
What is implied? A person sold a colleague 100 nuts for a dinar, and then it was discovered that he gave him 101 or 99. The transaction is binding, and the extra or missing nut must be returned. This applies even if several years have passed.
Similarly, if it is discovered that more or less money was given than the amount originally agreed upon the error should be corrected. This applies even if he performed a kinyan attesting to the fact that his colleague does not owe him anything. For the kinyan was performed under mistaken premises. Similar principles apply in all analogous situations.
...
...
Mácháne Efráim pontosan azt kérdezi, hogy alkalmazható-e adásvételre is a Kidusinban tanult din:
https://hebrewbooks.org/pdfpager.aspx?req=21540&st=&pgnum=68&hilite=
Ugyanebben az ügyben érdekes még Metivtá Kidusin 159. o. és Chidusé HáGránát (Naftali Trop) Kidusin 102. fejezet (274. o.) – ez utóbbi szerint chiluk: a kinján mesichával vagy dámimmal történik meg.
Ebből a Gemárából indult ki Ráávád (kérdés, hogy alkalmazható-e mechirára is, vagy csak kidusinra érvényes):
§ Rabbi Elazar says: If a man said to a woman: Be betrothed to me with one hundred dinars, and he gave her one dinar out of the one hundred, she is betrothed immediately and he must subsequently complete the payment of the remainder of the amount he promised her. What is the reason for this? Since he said to her: Be betrothed to me with one hundred dinars, and yet he gave her only one dinar, he is like one who said to her: Be betrothed to me on the condition that I will give you one hundred dinars. In other words, he betroths her now with one dinar on the condition he will pay the remaining ninety-nine in the future. The betrothal therefore takes effect immediately, and he owes her the rest of the one hundred dinars.
Ez pedig az alapvető din.
Rava continues: And that which we said, that if the brothers erred by one-sixth the one receiving a larger share acquired it and he must return the amount of the fraud, we said only with regard to movable property. But with regard to land, the halakha is that there is no fraud with regard to land. And with regard to land, we said that the halakha of fraud does not apply only when they divided it according to the value of the land. But if they divided it by measure and erred in the measurement, we do not say that there is no fraud. This is in accordance with the statement of Rabba, as Rabba said: Any matter that is according to measure, or according to weight, or according to number, if it turned out to be in error, even if the error was less than the amount that constitutes fraud, it is also returned.
Rásbá különvéleménye arról, hogy mit jelent a chozér: mekách vagy csak a többletpénz?
...