If the set of the triplets (x1, x2, x3) of the real number R form a vector space V3 then a subspace denoted by a vertical plane y = x can be obtained by a linear combination of sets:
1
(1, 1, 0) and (0, 0, 1)
2
(1, 0, 1) and (0, 0, 1)
3
(1, 0, 0) and (0, 1, 0)
4
(1, 1, 0) and (1, 0, 0)