| 释义 |
▪ I. ˈspanning, vbl. n.1
[f. span v.1]
The action of measuring, bridging, etc., with a span.
1775Ash Suppl., Spanning, the act of measuring with a finger and thumb. 1883Athenæum 24 Nov. 662/3 Increasing skill in the spanning of wide roofs. 1909Q. Rev. Apr. 344 The chasm yawned unspanned... A price..had to be paid for its spanning.
▪ II. ˈspanning, vbl. n.2
[f. span v.2]
†1. The action of drawing tight, making close, etc.; the result of this. Obs.
1527Andrew Brunswyke's Distyll. Waters L ij, The same water..is good agaynst the spannyng of the harte. 1592Shuttleworths' Acc. (Chetham Soc.) 74 Houpinge and spannynge of the vesseles, xijd; the porteres for loding the same wyne, vjd. 1597A. M. tr. Guillemeau's Fr. Chirurg. 21 b/2 These swellings cause noe payne, vnles it weare great spanninge of that parte might chaunce.
2. The action of fastening, harnessing, or yoking. Also with on.
1874A. H. Markham Whaling Cruise Baffin's B. 25 All hands have been as busy as bees, employed in the operation of spanning on, which literally means attaching the lines to the harpoons. 1882Schaff Encycl. Relig. Knowl. I. 87 Ritualistic..considerations forbade the spanning of different species of animals.
▪ III. ˈspanning, ppl. a.
[f. span v.1]
1. Extending or crossing as a span.
1823P. Nicholson Pract. Build. 122 The rafters were the sides of an equilateral triangle, of which the spanning line was the base. 1825J. Nicholson Operat. Mechanic 539 The height, or rise of the arch, is a line drawn at right angles from the middle of the chord, or spanning line, to the intrados. 1881W. R. W. Stephens Selsey-Chichester 155 Broad spanning arches, and high massive towers. 1889C. C. R. Up for Season 269 Where..you can gaze far away On the wide-spanning bridge.
2. Math. Of a subgraph, esp. one that is a tree: that includes and connects every vertex of a graph.
1956Proc. Amer. Math. Soc. VII. 49 The set of edges eventually chosen must form a spanning tree of G, and in fact it forms a shortest spanning tree. 1965Busacker & Saaty Finite Graphs & Networks i. 20 A spanning tree is a maximal subgraph of a connected graph which contains no circuits and is a minimal subgraph which joins all vertices. 1972R. J. Wilson Introd. Graph Theory iv. 46 Given any connected graph G, we can choose a circuit and remove one of its edges, the resulting graph remaining connected... We repeat this procedure with one of the remaining circuits, continuing until there are no circuits left. The graph which remains will be a tree which connects all the vertices of G; it is called a spanning tree of G... More generally, if G now denotes an arbitrary graph with..k components, we can carry out the above procedure on each component of G, the result being called a spanning forest (or skeleton). |