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数学专业英语-(a) How to define a mathematical term?
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# L' W9 j* y2 _: p. z2 }% ^ 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。 # h& ]& i) ~! P& a
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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。 9 d1 v2 ^ ? @8 n
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0 }1 ~3 y& w- B; C7 P% b% l! y% @ 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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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?; t6 M& H' ^# Q. z: Y
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( h3 g( t: n" f$ d% i: T6 r is defined as 5 Q* w) J9 F- x: w- Q. J7 C
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is called
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% t' I/ o) D' g1 B1. Something something - i( I5 n* \* p" k2 y h q
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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. # c( ]4 E0 r e% c; Z7 w* [! d {
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; {( P& G3 }4 b3 l2 U The mapping , ad-bc 0, is called a Mobius transformation.
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: |3 F5 @7 b+ C: I0 n is said to be % L9 c+ [" C1 e% T1 L
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2. Something something(or adjective)
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' g1 f% g! p* O5 |- i The difference A-B is defined to be the set of all elements of A which are not in B.
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; y0 V: [2 o' e% W A real number that cannot be expressed as the ratio of two integers is said to be an irrational number. 0 s6 Y0 f% \2 f0 ~5 y
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Real numbers which are greater than zero are said to be positive.
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E1 I6 \9 X3 s4 b$ B3 w% t2 ^ define
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4 U) D+ g4 ~8 i( ^: w3. We something to be something. * ~( D# C2 H; {1 h
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9 X+ H; J3 j% w g. [ We define the intersection of A and B to be the set of those elements common to both A and B. / u7 F- a o2 R
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& }; ^7 h P& E5 Z" q 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:
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is called , s# q: ]% @: G1 t2 ^ f
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is defined as
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is defined to be
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Let…, then…
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4 k/ x Y0 H1 t% N2 C% {2 Y 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. / Q# B" @" E6 L, G& v3 p) J
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Let d(x,y) denote the distance between two points x and y of a set A. Then the number + N% N2 k+ C2 h ]
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is called the diameter of A. / b' Y& @* ^9 x- a( I: h
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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: & W) W# y$ G8 E3 b" |+ x
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is called 7 s' _+ z8 {- S" _! t* D7 ^
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$ T3 W& O4 Q7 _) c5 t8 I- q If…, then…
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. H/ D. Y* O3 M If the number of rows of a matrix A equals the number of its columns, then A is called a square matrix. 1 D; _3 J" Z Z8 b$ ^* o2 Y" W
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& [* w! g4 E5 t2 H; U# C8 J' { If a function f is differentiable at every point of a domain D, then it is said to be analytic in D. 3 `3 T. a7 ?! P
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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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Suppose | …. If…then… …
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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. 3 |( S. q- g0 B
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