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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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9 p+ k; b9 A1 {3 n+ k2 v) \ 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。 6 n; [$ D- Q( [1 G* T- S
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# \. f! G0 O; _/ 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。
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1 c& A1 i) L6 h6 ^( L" r9 I 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。 . Z4 F0 Z2 _% p" ~5 K8 @
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(a)How to define a mathematical term?
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is called 3 N0 I# h6 K" `: q7 V1 L
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1. Something something ; V: C. w/ P' K" D$ a% ~
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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.
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5 b3 H0 p- N6 D The mapping , ad-bc 0, is called a Mobius transformation.
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1 ?( W# D) c; P/ H3 U is defined to be * s* I, M' z, ^, K
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3 w+ f ?0 B$ B$ I is said to be
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" w9 `1 p! o& \. R% ~6 N' j2. 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. V: p7 x1 N$ F# P, m& T# x1 K: U
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$ e3 w/ [9 ~6 T A real number that cannot be expressed as the ratio of two integers is said to be an irrational number. . m" |* q$ H% `
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- X: ]2 t& r; h Real numbers which are greater than zero are said to be positive. * G2 i. i3 O. j! `# X# j3 X
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define / l$ Z- ~; \; f5 c5 ?4 K
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9 D t/ O. d N- _* L/ v/ m3. We something to be something. " ]! I7 n! K- N) L" u
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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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( a# P- O1 m6 ?3 u7 t; b+ R5 o3 d We call real numbers that are less than zero (to be) negative numbers. % k8 O$ h0 q6 Y7 h! ~' i+ Z; [
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4 } ^* F& M5 c. |' @ 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:
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is called
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, }+ N; ~* o; T4 D1 w+ H is defined as
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is defined to be : N7 ]: N+ e0 C4 M$ W
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+ S- u1 u( q H0 H6 W Let…, then… . }/ n& k4 \! V
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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. + H& u$ r% g/ v( j! ~
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5 t% L7 Q0 s1 T( {; p5 j Let d(x,y) denote the distance between two points x and y of a set A. Then the number & j" D1 `& W3 N
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D=
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- A9 I: ~0 a* u; M' r2 V is called the diameter of A.
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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: 9 x+ ^: q3 f7 N s' s6 y6 h) v T
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% t0 N; j2 O- b; p U5 l6 t, Q; z is called
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is said to be
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is defined as
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, n* M9 X* |( O; i5 h If…, then… ; \) h2 F0 |. C# p# o
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5 p: L. N D! G* u- a. l ^6 J If the number of rows of a matrix A equals the number of its columns, then A is called a square matrix. 6 E* L/ V, U7 C: Z5 L9 v6 q9 A
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If a function f is differentiable at every point of a domain D, then it is said to be analytic in D. * \' S+ Y! \8 r- O4 V( y5 E2 h
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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:
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is called 3 l! r5 b" _, y) _
is said to be |
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Let $ w5 v) o5 @ b8 e2 }
Suppose | …. If…then… … : c3 F5 D6 _- G+ A: w+ x8 a
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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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