against them for fifty, for he says to him: “I paid one hundred and twenty-five. Fifty was on my own behalf, towards the hundred I owe as my share of the original debt, for which I have no recourse against anyone. The remaining seventy-five was paid under my guarantee for you and your two absent fellow purchasers, twenty-five for each of you. So repay me the twenty-five I paid on your own behalf, together with twenty-five, which is half of the fifty I paid under my guarantee for your two fellow purchasers, since you share with me in guaranteeing their debt.” He thus recovers fifty from him.

Section

The book then states: “If the fourth encounters the other of the first two, who has not recovered anything from the fourth”—meaning that the first man, who paid the six hundred and recovered three hundred from the second, encounters the third, from whom the second recovered one hundred and twenty-five, but from whom the first has not yet recovered anything. He means that this encounter occurs before the third recovers fifty from the fourth. The book calls him the fourth because three remain, making him their fourth, although he is the third of those who have paid.

The first therefore has recourse against him for what he paid on his behalf towards the original debt, namely fifty dirhams. He then considers the remaining amount he paid under his guarantee on his behalf, which comes to one hundred and fifty dirhams, whereas the fourth has paid seventy-five dirhams under his guarantee. The man who paid one hundred and fifty therefore recovers thirty-seven and a half from him, so that they bear equal amounts under their guarantees for the three: each will then have paid one hundred and twelve and a half.

He means that the first and third, who encountered one another, are the two whose payments under their guarantees have become equal. The second, however, has paid only seventy-five under his guarantee. This is because the first recovered three hundred from him, of which he in turn recovered one hundred and twenty-five from the third, as we have explained. Thus, seventy-five remains as the amount he has paid under his guarantee for the three, since one hundred was his own obligation, not a payment under his guarantee.

If the first and third encounter this second man together, they have recourse against him for twenty-five: twelve and a half for each of them. The first, second and third will then each have paid one hundred under their guarantees for the three remaining men, and one hundred on their own behalf. They are thus on an equal footing, just as if the two had encountered him together. Do you not see that if the first and second, who had each borne three hundred, had encountered the third together,