数学专业英语-(a) How to define a mathematical term?
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& s& m# m! h3 K 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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^0 s( k! v y1 ` 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。 . X2 X" i/ H; `( ^6 x( I* H& p3 J+ Z
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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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9 m$ D$ v- q T/ a 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)。 * I: K" y. d3 l% W1 T" H5 B
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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* ~, ~' u) h& d; j% [# n2 s (a)How to define a mathematical term?6 G$ N; I% L( o/ A6 N, v) C8 P
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is defined as - c: } l# e( D( ^
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$ t: Y8 h+ v. H9 x7 p1. Something something 3 K2 w4 R, J( ]- J$ Y5 @
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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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6 B& k% G2 b5 ] }+ F. V# a) v4 m The mapping , ad-bc 0, is called a Mobius transformation.
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is defined to be
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is said to be
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3 Q* `7 R3 r4 D7 M2 o' \! I, F# T2. 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. ; L0 ~$ m9 Z! f" i$ }
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A real number that cannot be expressed as the ratio of two integers is said to be an irrational number. $ s3 E$ q+ V i( W. @& l
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Real numbers which are greater than zero are said to be positive.
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define
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call
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0 c$ L( @4 [' H7 q3. We something to be something.
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6 S1 Z4 l3 K/ q$ X9 w( K' ?$ A/ k We define the intersection of A and B to be the set of those elements common to both A and B. 9 d2 {0 H# Z, ]1 {, M: {
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We call real numbers that are less than zero (to be) negative numbers.
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/ V" I7 t( L j4 F; d 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: ' o' L r- ^# R( d, S9 `2 E. Z1 I9 j
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is said to be
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, q: m) q7 r% h" W, n5 Y" q& ` is defined as & @; h& X4 K! |7 F r: a" a
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is defined to be
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Let…, then… ( l! w: Q- `9 @! D1 ]
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) }) v3 u1 ?6 k3 y r 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 2 t6 ?7 \# z* s2 W* ^
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is called the diameter of A. 5 U9 x( i# ~ N5 M6 C4 J
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- X* G: @$ E1 A/ O1 }1 d 5.如果被定义术语,需要满足某些条件,则可用如下形式: # D1 j7 [% j5 T1 N4 a$ E9 b
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& _$ H( R3 |7 u( [) G$ V is called
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is said to be
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If…, then… . o7 _ i% B9 j$ @
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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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7 M X3 j+ o# a( t If a function f is differentiable at every point of a domain D, then it is said to be analytic in D. $ G' k, k0 v4 R! R
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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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|, Q; F7 C! N: n _- Ris called
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% h% h5 t6 p. h/ D& ?* cLet
+ P! f: ^2 K9 E* Y% w. dSuppose | …. If…then… … / ?7 u% M( u* f- g# o8 o, |
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( ~5 n+ k. k s$ L2 T. f6 ~/ h8 V 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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