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数学专业英语-(a) How to define a mathematical term?4 R a1 |8 D, t0 ~5 R( h% X1 ]
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6 b, u3 p, O! i& v 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。 " k5 y% O( I% u
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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。 7 I: t& ]- B- ?6 D
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' R2 m! E+ v- V1 I6 J" { 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。 : t, R- D* {. u5 l+ h- u
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, b& s/ B/ |7 v" F- g 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?
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is defined as
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x, i2 D. Z& i/ S, x is called
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1. Something something 8 G8 X; }9 N2 V* I+ }$ x: E- t7 \! f
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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. ' g7 V+ I& ~3 F/ Y5 Z
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! O2 \7 i5 T, V9 C) c% i, k7 I The mapping , ad-bc 0, is called a Mobius transformation. " w& [( I5 T% }0 z( N4 n& o! s
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is defined to be
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is said to be $ r& w3 }! m5 x
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$ O" S; D! a3 h' r/ v) v7 Z2 a2. 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. $ \$ r. V! _# R! ?- @
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A real number that cannot be expressed as the ratio of two integers is said to be an irrational number. - M5 v) Z) s; s
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Real numbers which are greater than zero are said to be positive. 9 W' {9 i* @8 R
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define
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3. We something to be something. 7 Z x# B# P. C
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/ I$ D( i# r& @& [ 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: ; z' g9 f* T7 T
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is said to be , V7 |4 F) j4 Y2 o/ y3 a y# f+ H
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is defined as
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- L: [( I7 D# S# S8 }! | Let…, then…
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4 m8 J! H1 z3 m7 W" [ 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. + X5 Y+ l* n' a$ Q8 X7 W
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& w& Z! K7 T+ j" j4 N Let d(x,y) denote the distance between two points x and y of a set A. Then the number : a) x: Y% t- I
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is called the diameter of A. ; w0 \9 K; A/ b8 S# A! m% L
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. i4 a1 S: h, i1 S 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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is called # y8 _, z2 N1 x- Q
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is said to be ' w z- Y d5 F% O% [
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is defined as 2 ]) p, G0 ~& u- S
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1 W+ o7 N' Q5 j m If…, then… 5 c6 @" r" r0 V4 h# V/ c1 w. E
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/ {) Z: j. v( M4 l$ | If the number of rows of a matrix A equals the number of its columns, then A is called a square matrix. $ T+ d5 u, z" \" o. V( C; P
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" Y0 U( v9 e0 S' M8 C) R If a function f is differentiable at every point of a domain D, then it is said to be analytic in D.
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9 I8 G. @7 t* _* Q/ a: X, a 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: 4 P% a$ R3 ]5 [# ~. l, s
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is said to be |
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k2 [) k; F' p7 K, p' ULet ( @1 D. ` e7 H5 X9 a9 {* \# T
Suppose | …. If…then… … ; f- b( L+ W0 `( I
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7 }1 g" m, b+ W1 l5 b, b 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. % Y V% n8 }6 T, s* b" I
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