形变收缩

在拓扑学中，收缩（retraction），顾名思义是将整个空间收缩到一个子空间；形变收缩（deformation retraction）是将空间“连续收缩”成一个子空间的映射。

设 X 是一个拓扑空间，A 是 X 的一个子空间。那幺连续映射

是一个收缩如果 r 在 A 上的限制是 A 上的恒等映射；这就是说，r(a) = a 对所有 a 属于 A。等价地，记

为包含，一个收缩是一个连续映射 r 使得

即 r 与包含的复合是 A 的恒等。注意，由定义，一个收缩映射 X 映满 A。如果存在收缩映射，则子空间 A 称为 X 的一个收缩核（retract）。例如，任何空间以显然的方式收缩到一点（取常数映射为收缩）。

单词	retract
释义	retract /rɪˈtrækt//rɪˈtrækt/ 英汉-汉英词典 vt. 缩回；缩进；取消 vi. 缩回；缩进；撤消 n. 收缩核时态: retracted, retracting, retracts 名词: retractation 词组 \| 习惯用语您要查找的是不是： redirect vt. 使改方向；重新寄送 adj. [律]再直接的 detract vt. 转移，使分心 vi. 贬低；减去 retracts v. 缩进；取消（retract的第三人称单数形式） n. 收缩核；可收放起落架（retract的复数形式） protract vt. 延长；绘制；伸展 retracts v. 缩进；取消（retract的第三人称单数形式）; n. 收缩核；可收放起落架（retract的复数形式）; retracted adj. 可伸缩的 retracting n. 收起; v. 缩回；撤消；食言（retract的ing形式）; retracted position 内缩位置 retracting cylinder 伸缩筒 retract testimony 取消声明网络短语: Retracted 缩回; 可伸缩的; 翻供; 收缩; main-gear retracted 主起落架收回 retracting force 卷收力 tool retracting 退刀 Retracting stroke mm 伸缩行程 retracted flaps 收起的襟翼 Retracted Publication 已撤销出版物 RETRG Retracting 收回英语例句库 A cat can retract its claws, but a dog can’t. 猫的爪子可以缩进去, 但狗不能。 A cat can retract its claws. 猫能缩回爪子。 You may retract that statement. 你可以撤回那个声明。 A cat retracts its claws. 猫缩进它的爪子。 In hemicephalous larvae, the head and its appendages are reduced and partially retracted into the thorax. 半头型无足幼虫头部部分退化，后端缩入胸部，如双翅目的大蚊及一些寄生性膜翅目幼虫。 Right after the dental extraction,the interseptal bone distal to the canine was undermined to weaken its resistance and a tooth-borne appliance was used to retract the tooth rapidly. 拔牙后,可立即去除移动牙远中的牙槽间隔以减小骨阻力并黏结口内牵张器以快速移动正畸牙。 The main reason the Tsarist government retracted their ban was out of fear that receiving a Western European education would further radicalize women if they could not receive the education at home. 俄国政府撤销他们禁令的主要原因是恐怕如果妇女在自己国家不能得到教育，而在西欧能接受教育会使得女性变得更加激进。声明：以上例句、词性分类均由互联网资源自动生成，未经过人工审核，其表达内容亦不代表本软件的观点；若发现问题，欢迎向我们指正。原声例句小囧上周今夜秀 He's lost his medical license. The Lancet paper has been retracted. 因此他的医疗执照被吊销《柳叶刀》也撤销了这篇论文。刘毅突破英文词汇5000 A cat can retract its claws, but a dog can't. 猫可以缩回它的爪子，但狗不能。 newsroom What happened? - CNN had to retract. 怎么了 -CNN不得不撤回了新闻。实习医生格蕾第2季 Uh, Grey? Uh, get in here and help retract. Grey？过来帮忙牵引。美食家基地 That was offensive, I retract that last comment. 那很冒犯，我收回最后的评论。飘（原版） " I retract nothing, " she said briefly. But her mind was seething. " 我说的话，决不收回，" 她的话很简短，但心情极不平静的。双语版 TED-Ed 演讲精选 Unlike modern turtles, it couldn't retract its head into its shell, but had defensive spines on its neck. 与现代海龟不同，它无法将头缩回壳中，但脖子上有防御刺。日常生活医学科普 Strap muscles of the neck are retracted or dissected away. 将颈部的带状肌肉缩回或剥离。 NPR音讯 2019年8月合集 So now he's saying he won't accept the 20 million from the G7 unless Macron retracts that statement. 因此，他表示他不会接受2000万美元援助，除非马克龙收回言论。当月 CNN 10 学生英语 2020年11月合集 The vice president has recalled the governor and retracted his concession. 副总统拜登已经召回了州长，并撤回了他的让步。中文百科形变收缩在拓扑学中，收缩（retraction），顾名思义是将整个空间收缩到一个子空间；形变收缩（deformation retraction）是将空间“连续收缩”成一个子空间的映射。设 X 是一个拓扑空间，A 是 X 的一个子空间。那幺连续映射是一个收缩如果 r 在 A 上的限制是 A 上的恒等映射；这就是说，r(a) = a 对所有 a 属于 A。等价地，记为包含，一个收缩是一个连续映射 r 使得即 r 与包含的复合是 A 的恒等。注意，由定义，一个收缩映射 X 映满 A。如果存在收缩映射，则子空间 A 称为 X 的一个收缩核（retract）。例如，任何空间以显然的方式收缩到一点（取常数映射为收缩）。英语百科 Retract 形变收缩 In topology, a branch of mathematics, a retraction is a continuous mapping from the entire space into a subspace which preserves the position of all points in that subspace. A deformation retraction is a map which captures the idea of continuously shrinking a space into a subspace. 近义、反义、联想词近义词 v. renounce, repudiate, flinch, squinch, funk, cringe, shrink 联想词 retraction收回;withdraw撤消;refute反驳，驳斥;suspend延缓，推迟;extend延伸;reconsider重新考虑;detach分离;accept接受;deflect使偏斜;invalidate使无效;resign辞职; 英英词典 retract v. formally reject or disavow a formerly held belief, usually under pressure He retracted his earlier statements about his religion synonymous： abjure, recant, forswear, resile pull away from a source of disgust or fear synonymous： shrink back use a surgical instrument to hold open (the edges of a wound or an organ) synonymous： pull back, draw back pull inward or towards a center The cat retracted his claws synonymous： draw in
随便看	thirty day lethality Thirty Days thirty days clause Thirty days hath September thirty days notice thirty degree piezoelectric cut Thirty Eight thirtyeight thirty eighth thirtyeighth thirty fifth thirtyfifth thirtyfirst thirty first thirtyfive thirty five thirty five color film thirtyfives thirtyfold thirty four thirtyfour thirty fourth thirtyfourth thirtyish thirty minutes

retract /rɪˈtrækt//rɪˈtrækt/

您要查找的是不是：

网络短语:

形变收缩

Retract 形变收缩

近义词

联想词