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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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l2 w+ [9 o4 D' v0 ?; q 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。 - J% d. Y# K+ @8 U' ?) G5 @8 e+ N& w( i
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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)。 b' |" u9 \( V
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4 }' p) m$ N- ~4 g& Y/ I- j, T 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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* h) ?8 L5 n, S' P4 Z, ~ I& J is defined as $ l. Q2 k! e# X! h& [
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is called a" q3 e9 w8 g+ n8 z
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; y( |/ T& h4 X( H- q1. Something something
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, T# ?! j7 H9 _6 T G) \ The union of A and B is defined as the set of those elements which are in A, in B or in both. / ?: ]2 w3 R7 o! k p% n( w/ {
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The mapping , ad-bc 0, is called a Mobius transformation.
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is defined to be
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+ ]) _. d, P# ?. r) z" h is said to be , C* R& v7 s/ ?; M0 y, D
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9 E5 G' y7 o' Z* O a2. Something something(or adjective) ! X2 I+ d8 c1 a |' v3 c4 \9 X0 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.
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4 r: |) u) l. w A real number that cannot be expressed as the ratio of two integers is said to be an irrational number.
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Real numbers which are greater than zero are said to be positive. 5 U* e6 c: w# Z; ~8 Z7 f9 z& ]
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define
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3. We something to be something.
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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. 5 ~+ Y- J, l% g, X" V
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+ \( j' z- Y) n We call real numbers that are less than zero (to be) negative numbers. / e+ G+ B! m5 ^5 k
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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: 1 y. G1 ~2 V2 F
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is called : ?; S2 X0 C9 j
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is defined as , v, @9 L8 F0 k
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1 ^# w) J6 Y. y& k$ \! w Let…, then…
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, o$ B: D# O8 ~9 n: E# @ 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. , C a) x; Q/ o* 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 ) n4 M$ a- H+ ~/ L; b- f
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' z" ]- Z* X' \% W 5.如果被定义术语,需要满足某些条件,则可用如下形式: 0 y: Q" X6 x# f: k8 ]
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is called ' S5 q! t8 p7 |. p% {, t( J- O: `
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is said to be
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is defined as 5 v# L u' n7 P: X
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is defined to be 2 Q1 M& s# p+ o
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If…, then…
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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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+ x& \6 U: z% n If a function f is differentiable at every point of a domain D, then it is said to be analytic in D. ) {3 M. V" F" F, d; A+ P$ E
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- X* d1 h6 U8 A- F 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 " a% e/ c N$ F- b
is said to be |
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Let 8 Z" ?3 S: }9 Q+ D
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.
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