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数学专业英语-(a) How to define a mathematical term?
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数学术语的定义和数学定理的叙述,其基本格式可归纳为似“if…then…”的格式,其他的格式一般地说可视为这一格式的延伸或变形。
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& U+ ]. x1 ?9 A; r4 ? 如果一定语短语或定语从句,以界定被定义的词,所得定义表面上看虽不是“If……then……”的句型,而实际上是用“定语部分”代替了“If”句,因此我们可以把“定语部分”写成If句,从而又回到“If……then……”的句型。
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3 J& I. t9 x- E 至于下面将要叙述的“Let…if…then”,“Let and assume…, If…then…”等句型,其实质也是基本句型“If……then……”的延伸。 ' I4 `0 U& ]9 B; Q
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) S$ ]0 Z8 k$ `% `$ f6 R 有时,在定义或定理中,需要附加说明某些成份,我们还可在“if…then…”句中插入如“where…”等的句子,加以延伸(见后面例子)。
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总之,绝大部分(如果不是全部的话)数学术语的定义和定理的叙述均可采用本附录中各种格式之。
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(a)How to define a mathematical term?9 E% M1 Y/ z7 |" e1 I
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is defined as ; g6 n) i" V! u" m e. w5 ~
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is called
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9 J; J0 _5 F4 t. X. b1. Something something
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The union of A and B is defined as the set of those elements which are in A, in B or in both. 2 {+ ]+ m0 t( I, \) |
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( R" Y9 q( B Z! [# t The mapping , ad-bc 0, is called a Mobius transformation. ; n, I+ X2 g: t) D9 [( y
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4 x' j: u* ?0 L7 t is defined to be
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is said to be 1 v7 i+ x, a `& l" Z4 z9 `
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- S3 I3 ]+ l% T( _- t/ R0 B& u2. Something something(or adjective)
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The difference A-B is defined to be the set of all elements of A which are not in B. ; s, \% q+ C8 g# J; _$ |
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A real number that cannot be expressed as the ratio of two integers is said to be an irrational number. , h, H5 B6 {. h" Q7 S
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/ L9 v2 u# r; n' u( P Real numbers which are greater than zero are said to be positive.
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1 a v5 |5 A1 t8 V5 D1 U/ E j3. We something to be something.
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1 T6 e5 E- z$ z, b9 t We define the intersection of A and B to be the set of those elements common to both A and B.
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- [! Z) R& U' o$ i0 e7 S We call real numbers that are less than zero (to be) negative numbers.
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4. 如果在定义某一术语之前,需要事先交代某些东西(前提),可用如下形式: 8 z' W9 j, D9 s/ C+ l+ f4 R
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is called * e3 H5 c5 X! J$ ]
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is said to be 7 l, S. m+ M+ n+ Z: @2 A% J* r
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6 R, g: u3 u# A. D. e4 y Let…, then… & p: s _; L, }" C1 @$ z3 G
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1 o4 f, ^9 w$ j* ^' [$ t Let x=( ) be an n-tuple of real numbers. Then the set of all such n-tuples is defined as the Euclidean n-space R. O0 V/ z2 i/ w
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Let d(x,y) denote the distance between two points x and y of a set A. Then the number 8 T+ R3 K8 Z9 J$ }, I
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D=
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- U4 r, k9 b) u: U2 g( q is called the diameter of A. 6 l! n( }. @4 Z$ e& ^- T
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5.如果被定义术语,需要满足某些条件,则可用如下形式:
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4 }' _1 z( o% P0 j% k% ]3 i is called
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is defined to be
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If…, then…
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If the number of rows of a matrix A equals the number of its columns, then A is called a square matrix.
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9 s0 ~) Y/ o+ E. L1 `, B( o, H If a function f is differentiable at every point of a domain D, then it is said to be analytic in D. ) w: `9 a" I- Z0 b; K
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6.如果需要说明被定义术语应在什么前提下,满足什么条件,则可用下面形式: / F3 l+ N8 O. }
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is called
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Let
7 }$ m& q! t ~; ?2 @+ x2 PSuppose | …. If…then… …
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Let f(z) be an analytic function defined on a domain D (前提条件). If for every pair or points , and in D with , we have f( ) f( ) (直接条件),then f(z) is called a schlicht function or is said to be schlicht in D.
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