0 votes 0 votes Let A be a finite non-empty set with cardinality n. Let x and y be two of the elements of A. The number of subsets S $\subseteq$ A which include at least one of x or y is Set Theory & Algebra set-theory&algebra + – `JEET asked Jan 15, 2019 • retagged May 20, 2021 by Shiva Sagar Rao `JEET 364 views answer comment Share Follow See all 2 Comments See all 2 2 Comments reply Shaik Masthan commented Jan 15, 2019 reply Follow Share it is just like, find the super keys where Relation have n attributes, and have a$_1$ and a$_2$ are candidate keys. So, result is = $\color{red}{2^{n-1}}+\color{green}{2^{n-1}}-\color{brown}{2^{n-2}}$ red color part is for x (i.e., No.of super keys with a$_1$) red color part is for y (i.e., No.of super keys with a$_2$) brown color part is for intersection 2 votes 2 votes `JEET commented Jan 15, 2019 reply Follow Share Thanks 0 votes 0 votes Please log in or register to add a comment.