0 votes 0 votes A={5,{6},{7}} 2A = p = { ϕ, 5, {{6}}, {{7}}, {5, {6}}, {5, {7}}, {{6}, {7}}, {5, {6}, {7}} } I want to know is it right . If yes then why at element 6 ,7 there are two curly braces ? Set Theory & Algebra set-theory&algebra + – hem chandra joshi asked Oct 31, 2017 hem chandra joshi 237 views answer comment Share Follow See all 2 Comments See all 2 2 Comments reply LeenSharma commented Oct 31, 2017 reply Follow Share yes, right.and 6 and 7 have 2 curly braces because you have {6} and {7} in the set A not 6 and 7.Both are different. 0 votes 0 votes Rohit Gupta 8 commented Oct 31, 2017 reply Follow Share In Sets, Sets can be element of Sets. Here {6} and {7} are element of set A as pointed by @LeenSharma. 0 votes 0 votes Please log in or register to add a comment.