| 释义 |
intersection|ɪntəˈsɛkʃən|
[ad. L. intersectiōn-em (Vitruvius), n. of action from intersecāre to intersect. Cf. F. intersection (14th c.).]
1. The action or fact of intersecting or crossing; esp. in Geom. (see intersect v. 1 b).
1559W. Cuningham Cosmogr. Glasse 155 Then the meridian circle crosseth also..And so by these intersections [etc.]. 1570Billingsley Euclid i. x. 21 To marke the poynts of the intersections of the circles. 1658Sir T. Browne Gard. Cyrus 37 By Diagonal lines the intersection was regular. 1704Norris Ideal World ii. vii. 366 The necessary intersection or decussation of the oblique rays. 1842Mrs. Browning Grk. Chr. Poets 5 The intersections of sweetness in the rise and fall of melodies. 1860Tyndall Glac. i. xii. 89 We were compelled to cross at the place of intersection.
2. The place where two things intersect or cross, spec. (chiefly N. Amer.) = cross-road 2.; Geom., the point (or line) of intersection; the point common to two lines or a line and a surface (or the line common to two surfaces) which intersect.
1559W. Cuningham Cosmogr. Glasse 165 Applie a ruler from the Center of the Quadrate, unto th' intersection of the two thrides. 1660Barrow Euclid iii. x, Both circles have their centers..in the intersection of those perpendiculars, which is O. 1743Emerson Fluxions 234 The Axis of Motion being the Intersection of this Plane with the Surface of the Fluid. a1864Hawthorne Fr. & It. Jrnls. (1872) I. 15 We came to an intersection with another street. 1872Yeats Growth Comm. 42 These formed at their intersection a noble open place or square. 1931W. Faulkner Sanctuary xxiv. 231 He whipped the car in and out of traffic.., shooting recklessly across inter-sections. 1953W. Burroughs Junkie (1972) ii. 31, I had to pull over to the side of a road and wait until the weed wore off. I could not tell how far away anything was or when to turn or put on the brakes for an intersection. 1970Rand Daily Mail 28 Feb. 7/4 In the same way it does not matter that South Africans should say..‘intersection’ for cross roads. 1970Globe & Mail (Toronto) 25 Sept. 2/4 Two girls, 14 and 15 years old, were killed last night when struck by a car at the intersection of Park and Cherry Streets.
3. a. Logic. The relation of two classes that intersect, i.e. each of which partly includes and partly excludes the other. See intersect v. 2 b.
In mod. Dicts.
b. Logic and Math. The set which comprises all the elements common to two or more given sets, and no others; also, the operation of forming such a set.
1909in Webster. 1941Birkhoff & MacLane Survey Mod. Algebra xi. 313 Intersection and union are related to each other and to inclusion by a fundamental principle of Consistency: The three conditions X {slle} Y, X {intsec} Y = X, and X {union} Y = Y, are mutually equivalent. 1950W. Feller Introd. Probability I. i. 14 In the theory of probability we can describe the event AB in words as the simultaneous occurrence of A and B. In standard mathematical terminology AB is called the (logical) intersection of A and B. 1952F. B. Fitch Symbolic Logic iv. 101 For any two classes F and G there is a class [F {intsec} G] known as the intersection of F with G and having as members just those things which belong to both F and G. 1963Anderson & Hall Sets, Sequences, & Mappings iii. 50 A point is in the intersection of a collection of sets iff it is a member of every set in the collection. 1968E. T. Copson Metric Spaces i. 9 Let A, B, C be subsets of a given set E. Then the operations of union, intersection and complementation have the following properties: (a) A {union} A′ = E, A {intsec} A′ = ø. [Etc.] |