| 释义 |
convergent, a. and n.|kənˈvɜːdʒənt|
[ad. L. convergent-em, pr. pple. of convergĕre to converge: so in mod.F.]
A. adj.
1. a. Inclining toward each other, or toward a common point of meeting; tending to meet in a point or focus; = converging ppl. a. 1.
1727–51Chambers Cycl., Converging, or Convergent lines in geometry are those which continually approximate, or whose distance becomes continually less and less. 1794Martyn Rousseau's Bot. xvi. 198 The filaments and anthers are convergent or bend towards each other. 1835Browning Paracelsus v. 145 Some point where all those scattered rays should meet Convergent in the faculties of man. 1869Tyndall Notes on Light §79 Light moves in straight lines, which receive the name of rays. Such rays may be either divergent, parallel, or convergent.
b. of things immaterial, operations, etc.
convergent breeding: ‘similarity in external characters concealing fundamental differences of structure in different animals’ (Syd. Soc. Lex. 1882).
c. Composed of or formed by converging lines.
(convergent squint: strabismus in which the axes of the eyes converge.)
1831Brewster Optics iv. §39. 34 The convergent point of converging rays. 1862Sat. Rev. 8 Feb. 140 If General M'Clellan..meditates a convergent attack on all parts of the South. 1870T. Holmes Surg. (ed. 2) III. 248 Strabismus may be either convergent or divergent.
d. Biol. Due to or characterized by convergence (see convergence, sense 5); of similar structure but of different origin.
1871Darwin Descent of Man I. vii. 231 When man selects..the offspring of two distinct species, he sometimes induces..a considerable amount of convergence. This is the case..with the improved breeds of pigs, which are descended from two distinct species... In the case of the convergent pigs above referred to, evidence of their descent from two primitive stocks is..retained. 1897Parker & Haswell Zool. II. 416 A convergent or polyphyletic group, owing its distinctive characters..to the independent acquisition of similar characters under the influence of like surroundings. 1911A. Willing Convergence in Evol. i. 11 The distinction between convergent and normal morphogeny has long pervaded biological literature. 1953[see convergence 5]. 1963E. Mayr Animal Species & Evolution xiii. 388 It would be a great mistake to conclude from the convergent similarity of these populations that they are necessarily derived from each other. 1968R. D. Martin tr. Wickler's Mimicry vii. 84 It could be required that Müllerian mimetic species should have developed their resemblances independently, that is by convergent evolution.
e. Psychol. Of thinking, reasoning, etc.: of a kind that tends towards only one answer to a problem: Opp. divergent a. 2 b.
1956, etc. [see divergent a. 2 b]. 1964Language XL. 253 Such convergent–divergent differences are somehow replicated by cognitive differences in the speakers. 1971Nature 29 Jan. 350/1 Several studies suggest that science students perform well with reasoning or numerical problems which require convergent thinking towards a single correct solution.
2. Math. = converging 2, as in convergent series. convergent fractions: see B.
1816R. Jameson Char. Min. (1817) 208 A crystal is said to be convergent, when..the series converges rapidly as 15, 9, 3. 1858Todhunter Algebra xl. §554 An infinite series is said to be convergent when the sum of the first n terms cannot numerically exceed some finite quantity, however great n may be. 1867Wolstenholme Math. Problems 53 heading, Convergent Fractions. 1885Watson & Burbury Math. Th. Electr. I. 32 Hence the series P1 + P2 +{ddd}is a convergent series.
3. convergent-nerved (Bot.), (of leaves) having convergent nerves, ribs, or veins.
1882in Syd. Soc. Lex.
B. n. = convergent or converging fraction.
1858Todhunter Alg. xliv. (1875) 369 The fractions formed by taking one, two, three..of the quotients of the continued fraction a + 1 / b + 1 / c + &c. are called converging fractions or convergents..The convergents taken in order are alternately less and greater than the continued fraction. Ibid. 371 Every convergent is nearer to the continued fraction than any of the preceding convergents. Mod. The first four convergents of π (3.14159..) are 3 / 1 , 22/7, 333/106, 355/113 . |