Does this mean that there is still only 100% of stocks available and the ratio of iou's to total stocks 113/100? I guess that makes sense that a person can bor

Does this mean that there is still only 100% of stocks available and the ratio of iou's to total stocks 113/100? I guess that makes sense that a person can borrow a stock, sell it, borrow it again from the second buyer, sell it again. The number of stocks floating around stay the same, however, the number of iou's increases. Likewise, a person can buy the one share, return it, then buy it again, and return it again to settle the second of the iou's. Interesting that nobody is really explaining the mechanics of how this works. Makes me wonder if a lot of retail investors are about to get hurt.