∀ a ∈ R, ∃ ε >0, ∀ N ∈ [b]N[/b], ∃ N_( ε ):
|x_(N_( ε ))-a| ≥ ε
6)
∃ ε >0, ∀ δ( ε) >0 ; ∃ x_(1);x_(2) ∈ X: |x_(1)-x_(2)|< δ :
|f(x_(1))-f(x_(2)| ≥ ε
9)
∃ ε >0, ∀ δ ( ε )>0
∀ x_(1);x_(2) ∈ X: |x_(1)-x_(2)|< δ :
|f(x_(1))-f(x_(2)| > ε