/sci/ - Science & Math

>>12217653
That seems correct, yes. For the second problem, let's use the fact that 5 divides x if and only if 5 divides 3x (prime numbers 3 and 5). Suppose 7n + 2 = 15k. Then 3(4n + 9) = 12n + 27. What can you do with this?

>>12118979
What you are observing is the fact that the inverse image function induced by a continuous map is a morphism of lattices (order the topology using inclusion, use union for join and intersection for meet), and that the inverse image function induced by a measurable function is (should my memory not fail me now) a morphism of sigma algebras. This gives a way to give precise meanin for continuity or measurability by defining a function to be of that sort iff the induced function is of the corresponding sort.

Yukariposter. I miss him.