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数学专业英语-(a) How to define a mathematical term?
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, \+ @7 j. D3 `: p. W 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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, H. y& E; n; _- 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。 2 g9 v) E3 U, w" f" V6 Y
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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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/ V# g) R! H) C- K 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: C4 T5 \$ F* {) c
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0 F$ a) w/ }3 q' T; @3 B e/ }1 X 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?4 H0 m: I* i, B% N% L' \1 r4 R1 N
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is defined as ! K5 T& `7 |, v. r
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0 O5 Q' H" P! g* ? is called
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1. Something something ; p% T$ S' ?, u% X* |
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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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The mapping , ad-bc 0, is called a Mobius transformation. 7 x2 ]+ c7 U9 e% {0 M: I
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is defined to be % c/ R' X: a, n3 |, i6 C
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is said to be . X/ p$ l4 l0 _! V% R, O6 ~5 Z
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. Y T4 F+ T! G+ ~8 U2. Something something(or adjective) / c. G2 D0 z ~5 F$ o E
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The difference A-B is defined to be the set of all elements of A which are not in B. ( v& [% ~+ c- y1 w/ Y
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A real number that cannot be expressed as the ratio of two integers is said to be an irrational number. % N) A, F0 X7 w# t% m3 H
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: ^; n1 }* O0 e; D/ D define 6 g: \ n+ T4 I+ q9 ^
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8 o) n# U) A# `! g s7 Z3. 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. 4 o' x- Q- M) f
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0 N' i& t: G/ i# i: S, u$ u' } 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: ! { D2 a: n1 @* L7 L r8 [
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is said to be
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is defined to be V8 C& F: E/ P
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% L5 w- g3 T8 `2 k& j' k' q Let…, then…
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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.
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Let d(x,y) denote the distance between two points x and y of a set A. Then the number
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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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. N: F2 Y' D/ M0 F is called
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is said to be 6 S: a3 s" Y. _2 K, g2 y
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is defined as
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6 F% ~5 w4 K9 f& |5 { If…, then… / i+ ^- ?. U z3 A1 L o
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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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- o) s* L4 i( F/ }3 S 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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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 " w: B( f! Y/ ^% v$ Q3 u
is said to be | ( U A' A: b, h M6 f" F
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Let 9 O' @2 K7 o& q6 f) K( `; q
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. $ X; ]5 [. d" N; H' r
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