(∫_1^2)(ƒ(x)) dx = F(2) - F(1)

A set X ⊂ℝ is said to have measure zero if for every real number ε>0, there exists a finite sequence of open balls (I_1,)*(I_2,)*(I_3)⋯ so that

X ⊂∪ (I_i) and (∑_i=1^n)(|(I_i)|)<ϵ

From the isomorphism theorem, we have

G\Ker ƒ≌im(ƒ)