Besonderhede van voorbeeld: -7930645861209836101

English

Note that if any two sets are separated by a function, then they are also separated by closed neighbourhoods; the neighbourhoods can be given in terms of the preimage of f as U := f−1 and V := f−1, as long as e is a positive real number less than 1/2.

Spanish

Nótese que si dos conjuntos cualesquiera son separados por una función, entonces son separados por entornos cerrados, tomando los entornos como preimagen de f de la forma U := f−1 y V := f−1, con e un número real positivo menor que 1/2.