数学专业英语-(a) How to define a mathematical term?: S% h( ^1 v, w- p
; ?+ l% |* p0 t- X ?! n
. A6 E- h; h) p. A7 a$ Q + w' @6 T3 {3 `, ?
# z( L9 Z; E% \1 w- n" e
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。 0 B. [3 i- l1 D; [
- L" f6 |3 L( ]: p8 k( Y( N
; |! N' Z3 K/ _9 F) V8 K) M" z# _6 Q # v3 @+ c4 f5 G x$ s
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。 0 q9 w) ~# S# n
/ n4 X( q! Q& Y: q " g* e. D9 B5 x1 n* l
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。 - P4 \1 }0 |! {& x
2 H7 I+ O' `6 p4 g' f: O9 ? / o i h" r( y& c& [
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)。
T) _7 ]: j! z0 _ + r& @ y# x. c' k( N' c
3 g: `$ j; d" Q8 H) R 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。 4 J- W6 q1 v0 b' o/ E
3 _: |: L& D7 z6 J6 J- t " H! U( B1 T" l4 e. y: U, }) V
6 m8 m: Y5 a7 _. r& [7 d$ e7 }
5 a! A& ?- o' z8 D3 r+ a : I$ z) `. D4 P2 [. K4 `+ S
5 i. l! Y3 g& y/ P" v. b
" n( A( V; w# E9 J/ `! q/ W
7 L, t2 B7 X1 B+ N& ] (a)How to define a mathematical term?3 |" e. N7 E- H# G( R- U$ e
% J- f, \* P' Y5 L. K. Q3 O; h/ c8 O5 m% m/ G3 _ X1 P
$ t. L3 j8 ^6 Z: c/ a! c' |7 c _
" D4 j* h% _6 I0 x+ O2 X
) M1 q' v% f& K- f. e) ]4 ^$ u+ D9 h3 H5 w$ U5 X7 y' U6 \3 ?
+ N" i; ?6 E+ b% y& n
is defined as
6 v1 s6 Y: I' u3 X- c9 ~4 ]( p6 _
# I2 p# m% G8 C4 w+ ]1 _1 }
is called / ]" `. f2 ?; i
. u6 B, A: q1 r* M | 3 g- y; t& N3 _# W
1. Something something
4 F9 u3 i8 b4 |
1 ]! j# B3 q* j: l; J. k |. d9 Z
. `4 i/ L* f3 Z
( R. L o: Q* Y
' @( S }+ Z5 y6 L7 x& I $ C2 J' A5 x( T* v6 B' C
# ?7 R. E& ?+ I( `: F. X1 q5 I4 E0 O
( ?8 z2 ?- Q p3 a! j 7 q* `3 v6 K2 p3 [" a- n
The union of A and B is defined as the set of those elements which are in A, in B or in both.
3 f5 D3 g: `6 b% d7 k/ O" `. k1 S/ {0 e9 r5 G! B- a) r
8 q+ L( e4 x7 g The mapping , ad-bc 0, is called a Mobius transformation.
0 q5 s9 J- Y4 [- r2 c* V+ s2 _" U* \) i% f7 j$ {
: o2 X7 z4 r; C) q' s/ ]
9 A3 U" L, B! g t) Z4 M; r; |
( U" u* |1 h/ t+ V5 _
, S9 x' a" L/ F2 H) e5 V9 G, f* B$ q1 I( q4 ^4 x
is defined to be
0 l4 B7 v0 u0 x! \# O. e
) U6 m% r- ^: I7 k0 n' f ; P: y' @: ]; ?2 d
is said to be
: p+ S7 m0 J4 h
; l5 {+ A# U: h |
8 W& A) ~* a- E2 L! b2. Something something(or adjective)
8 W5 {. w% ^# \* G9 l$ p
! ?1 ]% s, y, A& }4 x0 V: t( H # z! J- O' G1 G7 l
4 D, } C3 y5 W7 ^$ j! W/ C; {& ?) H; P
' H" }9 W; p2 v- n/ L2 b# Z! D7 o * ?# v$ |* i& W# ?7 n
; \5 U& F% {# y# n* `& v ! q6 _, [; G. k- z9 {) O. d2 X
The difference A-B is defined to be the set of all elements of A which are not in B. $ l5 T9 S \+ i5 L8 p
. g& G! z! Y! d2 u
" ~/ E! t8 f* t! T8 ~ A real number that cannot be expressed as the ratio of two integers is said to be an irrational number. & A# {: F- d2 h
7 Q$ _( J6 ?0 }
( B T3 J1 C/ R0 ~7 w+ Z! _- f4 l' i4 z Real numbers which are greater than zero are said to be positive.
0 q* E) d) D* Q% y2 ~/ }! N; y/ u
; ]4 [3 Z% e2 ]4 K1 D0 N' ~- ~& ?
, s) K) Q4 _& v+ w
. S! Y% b, |2 h5 F# k* R3 u; ^
8 f5 b7 E( T! m/ U; L- @4 B3 R( e; {$ O/ w: b8 g2 Z
define 7 \% d G) r2 C+ m* e
3 W& j n! T8 c
3 `- m" K& q" ~ call
+ e0 O( C: Z8 \' x0 l( t: I6 V8 _9 j1 |9 U! Q" q
|
1 R6 I! E) r' W3. We something to be something. ! W# v* M6 S4 e
/ e- N0 D) y4 M7 M, c7 u ) v$ ~2 {1 ? r; V- A8 t0 s* M
, }( C/ b2 { u# u3 Z6 N; X3 K7 b2 s7 I! g3 E- \6 \. U& J0 d
8 S+ V$ n% M* ]$ K/ ?5 z6 R( f 2 \. p- r2 S1 w y% _
( E* Z7 u4 w& ?2 A8 R! g0 n/ e
/ Q& u9 [ L e t* t* `2 b We define the intersection of A and B to be the set of those elements common to both A and B. ' z& u, K# Y4 b
2 i. |1 p V8 q1 l( a
4 ]9 x1 a% r1 o& }- \ We call real numbers that are less than zero (to be) negative numbers.
4 [+ \% @# w: J1 I6 j# |
, `2 O8 g0 K- O* l
* _0 L5 I3 S. h1 Z* h 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:
5 s$ b2 U; w; N9 Y5 t
: F5 L5 S+ K0 l3 h$ _6 O
0 e6 k; A" {0 A! k7 ^ & I+ M, T+ W1 W. u
6 c- d) M% D# T! O/ U
+ p+ h* R- n* |8 x: R; ^
, g* ?7 O% w7 R! @; |, s! a0 N' M c" v. b! J+ m
+ W8 t# z0 v! l* Z, [" l
0 k' T( E3 q$ p# o- A$ M1 S( v; B, W, w3 a) Z) m
/ c/ n* W, `4 \0 u5 B1 a0 D9 X2 i: x
m9 p o/ R6 \- \5 P2 }/ u is called
0 y! E/ q1 q8 F' u' r: P9 m$ J( A R* I- |/ M; E
& B6 `/ x; {% P" t4 [0 S" `
is said to be
- }. x6 D5 ?" H @. S. R2 J! @
- ` {% u4 u m7 }: S 1 ^7 @* ^; }, v9 G/ Z$ ~
is defined as " r1 d7 m2 y8 b L, \* M: @
0 f9 a, a3 e, c & A$ F+ Q4 s2 T
is defined to be
- Q; W- T; a- g, ^7 f
' W# i; O' ^8 o @ |
6 Y) C% U( }! l4 z" n Let…, then…
- ^$ ~" W* y% K- v& E" q2 r2 I
, p8 r3 C8 R) W$ w' N# n 9 W" [' F' I N% r# w3 [
# M0 R* {8 p+ X% N) ]
0 j; k" B. z% L4 f2 N, N
( J# u. g1 i h3 B) d5 `+ I2 n& i: E 0 v) W# ^, Z9 y; d0 {
! O3 m: o8 A1 i s4 n: k3 q X
: x% _2 U7 ~) \* N, ?
2 o& ]- ?0 U+ V& R
$ H) a/ [* ]- A9 x$ f5 z) H1 K# }
' A8 M% q- {7 c; M e
2 J a; A0 r; O* G L , d) S$ j% K& ^8 N3 {" N( v
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 ]8 B p9 L, o2 X* ]+ _! v8 r
/ v& u1 O9 j# b! n: p$ t o 5 H9 v: T- M6 t
Let d(x,y) denote the distance between two points x and y of a set A. Then the number
r" t! a( K% b7 e9 P3 D+ D( x @, e2 ]" O; f3 m8 d
) x' y3 [% A. }* K5 a
D=
7 Z* D; a1 ]* Q( C
( d( x+ o8 m) Q
' E4 D$ T) n7 S6 o7 F: N+ G: u is called the diameter of A. 4 k& f, {! W: l/ {/ I4 X5 E
0 h1 i( N! B+ s" \. M ( Y2 ^& V: ?8 Z
5.如果被定义术语,需要满足某些条件,则可用如下形式: 1 Y0 w* h M& [
. A& t! F$ c2 m( v 2 ~4 R. U) f Q8 k: G% c
! u; |/ X1 |- @" M6 B4 F' e0 G9 l& r0 l; g1 Y7 P6 |6 E6 g+ }) _6 Y
! ^# G( t4 R3 \: P
- T2 W7 J" q. z6 `6 Q/ M is called
; S1 k$ F$ X& `6 K- e! o( n2 r- B+ `$ Q5 [0 L! @, g: x6 G
2 `6 q9 {8 M4 f# Z7 E0 M is said to be
" f) p+ i- x2 U; Z" A' A8 a/ [ ]$ q0 T+ H5 F
# R; @. I3 N+ } is defined as
6 a* y4 H, A% }0 G3 S0 }9 N$ [( x
3 @1 Y- f0 f! N. l( ]) ^$ O- Z& z
, A! m0 v$ G0 C: \5 A is defined to be & Z" C# Q, {. a4 A' l5 o8 h
% R ]) u" ?: ]4 ^9 o' x# x0 | | % m7 N1 r' A* w, e
If…, then… " D" v k. ~# o B, Z0 S% V" b
# Y: M9 r+ t: l B$ ~; I: u ; @- M0 q' M. S- t1 k, K
$ M& _$ }! X& A- s9 _! w# a1 } q. U5 K' Q- p" a. J- x2 y
_7 M1 q1 T& J# N) S
2 _% D- [2 B- {: c9 {' @' p8 H f
2 N& k# w$ A6 v9 V z0 D! N& ^
" D+ q1 r5 C% ^( G0 P1 [ 8 _) G1 H& a! S) F
5 d( Z* L4 e6 A" @5 F 6 I! b! j" }( a6 J6 @6 i
) \4 E5 c- _3 Y0 W, r9 ] q& e
" U0 ?$ V% Y7 R7 @7 A 0 k, X7 y2 E* f6 c6 i: `
If the number of rows of a matrix A equals the number of its columns, then A is called a square matrix. 0 r2 [! l* t% J. W# D; C( f, ]
1 n* x( q" }: P2 f4 i3 N/ U p& h8 `, j) G {- }2 l6 X9 d
If a function f is differentiable at every point of a domain D, then it is said to be analytic in D.
$ \" G! R% X9 a3 S) _
9 s4 Z1 N/ _9 Z* b/ t( F * z1 `7 k+ P( _1 l: y' z5 N
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: , p& p9 `( n7 C# G1 W
$ U1 h, ~+ p% w# L
' L; C) C0 }' m
) \" H7 _' i8 X
5 M$ }7 q) L/ Q/ v( s. G3 i
* R" o" C0 }/ o
' k0 g" s. Z) U* m& [8 B9 C/ G
6 y! Q, s- V: F7 u9 E6 z* I" r9 l7 F8 v$ z0 ~/ U
is called # o$ S4 e8 x, D1 g) M* [: @
is said to be | ( m- l) z, |! M
" s7 ^: N" D% s8 [7 u2 A
' F& L' \1 p" s& k o
1 R$ n) |' h, p
3 F q% G @ i0 o9 J& r' h, ]% b1 P& g J
Let
$ i. K* b6 z5 w9 Q; T1 qSuppose | …. If…then… … ) l; T) }4 L9 i7 b9 t9 u% u
% |- m$ G2 t( a1 A$ n3 k% O
; v- I7 o6 m; N3 c# U' t: G 9 b8 B3 |# w' \" Z; @# P8 n5 W
8 R, T# c# \7 R( W) q! e: b
: q4 z6 u0 w1 F/ [; W0 T7 |0 V
+ A; G5 n" m, t# X& F9 M
/ Y( J) F K' Y4 D6 |0 k% E0 V 4 W( [# t9 N# R
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. ; h- R% p) R0 a/ p& w9 |
8 Q% I6 p( ~) I
( }0 k5 P1 c4 T) c8 s- Y / d* M6 L3 C* }* ^2 G+ z
G: V) `8 ]" ^! v
|