A property that holds for all $x$ in some residual subset of a Baire space $X$ is said to be generic in $X$ , or to hold generically in $X$ . In the study of generic properties, it is common to state ``generically, $P(x)$ '', where $P(x)$ is some proposition about $x\in X$ . The useful fact about generic properties is that, given countably many generic properties $P_n$ , all of them hold simultaneously in a residual set, i.e. we have that, generically, $P_n(x)$ holds for each $n$ .