Past exam of the year 1 of the computer science course of the University of Oxford / 2022 / Digital systems, linear algebra, introduction to formal proof / 8 / b

Express that the order is a dense order:In either real interval, $(x+y)/2$ lies strictly between any two distinct ordered elements and remains in the domain. In the integers, $x=0,y=1$ have no intervening integer, so this first-order sentence is false. The endpoints of a closed interval do not prevent a dense order.