> ℤ ⊂ ℝ
That is not at all obvious without some canonical isomorphism acting on ℤ, or at least is a behaviour strictly dependent on your particular set theoretic construction of the reals.
E.g. for the cauchy sequence construction of the reals, the image of the integer 1 under this canonical isomorphism would be the equivalence class of the sequence (1,0,0,0,...), but these are of course not the same object in a set theoretic sense.
!!!!!!
The integer 1 is the same as the real number 1 ,is the same as the odd number 1, is the same as the perfect square 1, etc.
ℤ ⊂ ℝ
That this is the top-voted comment on this thread.....