作者LuisSantos (我討厭當好人)
看板Math
標題[分析] 請問幾題實變
時間Thu Oct 1 19:19:49 2009
1.
Suppose that |f|^p is Riemann (improper) integrable over the domain Ω
p
(but not continuous) , does f belong to L (Ω)?
To be more precise , for such an f , is there a sequence
f belonging to C(Ω) so that
k
p
lim ∫ |f (x) - f(x)| dx = 0 ?
k→∞ Ω k
2. Is there any function which is not Riemann (improper) integrable but is
a ||˙|| limit of continuous function ?
p
n p
3. Suppose Ω is contained in R , and f belongs to L (Ω) . Is there a
∞ p
sequence of smooth functions {f_k} so that f → f in L (Ω)
k=1 k
as k→∞ ?
n
4. For Ω contained in R open , for ε>0 sufficiently small , define the
open subset Ω of Ω by
ε
Ω = { x belongs to Ω | dist(x , boundry of Ω) > ε} .
ε
∞ n
Define η belonging to C (R ) by
{ C(e^(1/(|x|^2 - 1))) if |x| < 1
η(x) = {
{ 0 if |x| ≧ 1
with constant C > 0 chosen such that ∫ η(x) dx = 1 .
R^n
For ε> 0 , the standard sequence of mollifiers is defined by
η = (ε^(-n))(η(x/ε)) .
ε
Prove that ∫ η (x) dx = 1
R^n ε
_______
and supp(η ) is contained in B(0,ε)
ε
5. Prove that all norms on R^n are equivalent .
以上這5題實變
請會的人幫我寫出詳細的證明過程
謝謝
Q.Q
--
本週抽中:安 心 亞 本週最心碎:吳 怡 霈 本週最亮眼:王 薇 欣
動園木萬社萬醫辛 麟
六犁科大大忠復南東
中國松機大
劍路西港
文內大公葫東南軟園南展
物 柵芳區芳院亥 光
張 技樓安孝興京路
山中山場直
南 湖墘
德湖湖園洲湖港體區港覽
○ ○○ ○ ○ ○
◎ ○ ◎◎ ◎
○ ○ ○
◎ ○○
○○○ ○◎○ ◎館
王樺邵艾絲小樺張甯莎
王欣李慧啾豆妹安亞
吳霈廖嫻小
徐翊舒虎
瑤可蜜兒蔓小劉萍 林玲
彩 庭莉 欣 鈞 拉
薇 怡 啾花 心
怡 書 嫻
裴 舒牙
瑤樂雪 蔓蔓秀 志
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.115.189.53
→ doubleN :3. (f*η_ε) → f 10/01 21:08
→ doubleN :4.變數變換 10/01 21:08
→ doubleN :5.請參考泛函書籍 10/01 21:09