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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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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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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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$ X% f8 C4 b3 j+ x d/ D 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)。 $ c$ ~* J u6 w9 s: i2 W4 ~( s
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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。 1 |1 Q$ ^# p0 B
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$ C3 D& |+ V# }) F5 D( B (a)How to define a mathematical term?
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is defined as
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8 L7 C5 V3 c9 e is called / g( B+ }' {& C2 O" g8 X5 N- n4 w
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3 c' g- D: g# V( j+ i" ^, d1. Something something }4 E# Q; a7 p' ]
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+ ~& M+ T6 @" K& @' ]* \ 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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% v) ]) e; q7 S5 }/ n2 a: _ The mapping , ad-bc 0, is called a Mobius transformation. 3 _4 X4 j( _& d0 v
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is defined to be ! e1 ]# s7 J/ V! y1 p6 O" F8 a
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% o' z4 |) I3 ]2 ?8 A z is said to be
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6 x9 x# `8 \+ ? p2. Something something(or adjective) , Y- @9 t/ b* L3 d3 \5 h
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The difference A-B is defined to be the set of all elements of A which are not in B. G. ]9 C! ~% n' Y" p+ T/ q
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9 S5 M; ?, i3 }9 Y4 Y; c A real number that cannot be expressed as the ratio of two integers is said to be an irrational number.
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( U! ], A$ u& z! U" [ Real numbers which are greater than zero are said to be positive.
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, h( P: x x' p! i' V, M+ F define
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call
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3. We something to be something. 5 m( X) l2 A2 n) C
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9 ]/ i5 ~6 e# B We define the intersection of A and B to be the set of those elements common to both A and B. * e, q8 g; R6 c' |
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9 ]* F" Q8 a7 ]2 e4 Y. s3 [8 V) o We call real numbers that are less than zero (to be) negative numbers. ! X3 L8 H7 K% Q( ?. l; A, T
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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: / _" ~! E5 M X4 t
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0 y9 `5 ~& n& s: Q, h8 \' G is called
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is defined to be
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8 t0 v: Q$ v* G8 n7 F Let…, then… / D7 D* u& v" l/ \: r' n; W
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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. 3 f( i1 D* m. D9 o" Z) H9 l
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& @4 W* w# [2 z2 ^ Let d(x,y) denote the distance between two points x and y of a set A. Then the number
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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:
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is called
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4 L0 L1 F3 z6 M/ j is said to be 4 F' E; y# O# H8 }
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is defined as }7 m0 l- i+ v! e) C& t
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- {9 K9 G# O! W5 d9 U- n7 I If…, then…
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2 Q8 V" j1 l4 `9 {2 D* h1 l" b If the number of rows of a matrix A equals the number of its columns, then A is called a square matrix. - O& A# x/ k7 H: y2 t
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; G$ o# F( N# z0 g- T( d6 J If a function f is differentiable at every point of a domain D, then it is said to be analytic in D. " _7 h. P% {3 \' r, ^
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$ L4 `; O, X: Y3 k" \9 \ 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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# V4 @" Q) }, |* }5 r& v+ R9 A: qis called ; S& P: E& o& Z4 p: b
is said to be | 3 d; ]; K- c. o5 j$ T" f
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# ~! I% J+ k5 Z$ f- y1 w! @. |5 W" k* `0 |Let 5 S: K& D2 W* x% R
Suppose | …. If…then… … 7 B* Q$ I0 @3 j
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l+ J- A& d8 I' } _/ R* i 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. " z5 a% v7 X+ B8 J( m5 v$ [/ a
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