You said "these are some of..." not "some of these are...". "X1, X2, X3 are some of Y" means that {X1, X2, X3} is a subset of Y. "Some of X1, X2, X3 are Y" mea

You said "these are some of..." not "some of these are...". "X1, X2, X3 are some of Y" means that {X1, X2, X3} is a subset of Y. "Some of X1, X2, X3 are Y" means that {X1, X2, X3} intersects Y. But you said the former!