• 沒有找到結果。

Let (X, B, µ) be a σ-finite measure space and f a nonnegative mea- surable function on X

N/A
N/A
Protected

Academic year: 2022

Share "Let (X, B, µ) be a σ-finite measure space and f a nonnegative mea- surable function on X"

Copied!
1
0
0

加載中.... (立即查看全文)

全文

(1)

Real Analysis Homework #8

Due 11/24 1. Let (X, B, µ) be a σ-finite measure space and f a nonnegative mea- surable function on X. Prove that for λ := Lebesgue measure, R f dµ = (µ × λ){(x, y) : 0 < y < f (x)} (”the integral is the area under the curve”).

2. Let (X, B, µ) be σ-finite and f any measurable real-valued function on X.

Prove that (µ × λ){(x, y) : y = f (x)} = 0 (the graph of a real measurable function has measure zero).

3. Let (Ω, B, µ) be a σ-finite measure space. Assume that φ : [0, ∞) → [0, ∞) is strictly increasing and φ(0) = 0. show that

Z

φ(f (x))dµ = Z

0

φ0(t)µ({x : f (x) > t})dt.

4. For I := [0, 1] with Borel σ-algebra and Lebesgue measure λ, take the cube I3 with product measure (volume) λ3 = λ × λ × λ. Let f (x, y, z) :=

1/p|y − z| for y 6= z, f(x, y, z) := +∞ for y = z. Show that f is integrable for λ3, but that for each z ∈ I, the set of y such thatR f (x, y, z)dλ(x) = +∞

is non-empty and depends on z.

1

參考文獻

相關文件

Algebraic Methods in the Study of Compact Riemann surface All the Riemann surfaces are assumed to be connected.. Let X be a

Notice this example shows that pointwise convergence does not imply continuity and note that area and derivative may not be preserved by pointwise convergence.. (f) Let f m (x)

Let {f n } be a sequence of real-valued continuous functions on [a, b] which converges uniformly to a continuous function f on

Generalization Theorem Let f be integrable on K = [a, b] × [c, d] to R and suppose that for each y ∈ [c, d], the function x 7→ f (x, y) of [a, b] into R is continuous except

The proof is left to the reader as an exercise.. If f is differentiable at x 0 , its derivative

[r]

Cite Definitions/Lemmas/Propositions/Theorems proved in class as many as possible; You need to indicate which Definitions/Lemmas/Propositions/Theorems you are

Let I be the closed unit interval [0, 1] and X be a topological space. We call this topology the compact-open topology on