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数学专业英语-(a) How to define a mathematical term?- I3 f# D: {; |' s% k. W
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+ V! o, r# D. d" ]% n+ \7 s 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。 F5 `7 d6 D% H. M
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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。 5 w( k1 D; w' J* Q% ~1 }
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& t% i/ k& U2 |1 v 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。 ( }2 L/ N, W* K- f+ \& Y6 B7 K! p
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( E+ i/ B# o- H" \ 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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$ q, g4 t/ d' l7 W+ i9 }3 A 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。 # \! n1 D+ e7 |1 y" { q% Z
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1 u: X! G6 U5 \ (a)How to define a mathematical term?
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: B; e& F0 b4 N- a" x7 a is defined as
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is called : Y- c2 x- J+ m* l, Z; p+ @+ Z
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' f5 _# \. u; ?; j1. 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. # h0 @7 Q3 w7 \7 g% F6 m
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) L) ]/ S$ l. e7 l/ e/ r The mapping , ad-bc 0, is called a Mobius transformation.
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: r6 y; E( M: ^% e8 K! a. \ is defined to be $ b \. i( h+ g% S
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2. Something something(or adjective) 2 c* W! J9 X. R. ^
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The difference A-B is defined to be the set of all elements of A which are not in B. 1 @" ]2 T* v2 t9 X- u
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! L' ~4 Y0 O1 E1 k7 J A real number that cannot be expressed as the ratio of two integers is said to be an irrational number.
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' Z& a& Z7 B! R' U Real numbers which are greater than zero are said to be positive. 8 n7 \+ L- `2 l
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3. We something to be something. % B8 c9 Q0 s' R: f! }. a+ o
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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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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: 7 Z2 z- s& M: J7 t, e/ V& N
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is called # b9 r; D+ h0 {6 L* Z6 p
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# ]+ T$ J# K0 V) t2 ]8 V% b# j is defined as
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is defined to be $ I* J. ~5 a# B! k
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Let…, then…
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5 E6 k7 f( m; U9 l 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.
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Let d(x,y) denote the distance between two points x and y of a set A. Then the number
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+ I7 k' B/ O6 D8 O3 _# M 5.如果被定义术语,需要满足某些条件,则可用如下形式: * k* _9 X0 h8 z1 _) u7 p
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8 h) ~* h. H' R( ~# F# J7 |4 t is called : @# k! k- E8 Q9 i& {
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is defined as 7 O$ e1 w$ U2 h1 y
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is defined to be ' c$ r. D! p5 N
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: ^3 @- H% T2 v; E h5 ] If…, then… . p4 Y$ g2 I. h3 Y6 f
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$ ~% Q. J8 b+ `' {+ I3 x1 P 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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If a function f is differentiable at every point of a domain D, then it is said to be analytic in D. ! Y8 B* d2 C$ Y" \
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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
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Let
( v& F/ a, W7 x& G0 S5 kSuppose | …. If…then… … 7 m& X/ N. L& x1 E/ L
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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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