Definition. A flow network is a directed graph G = (V, E) with two distinguished vertices: a source s and a sink t. Each edge (u, v) ∈ E has a nonnegative capacity c(u, v). If (u, v) ∉ E, then c(u, v) = 0
Example 1. 1. The iterative rule po 1 and pk+1= 1.001pk for k=0, 1,..pro- duces a divergent sequence. The first 100 terms look as follows: P1=1.0170=(1.001010001.00100 p2=1011=(1001)(1.0000001 3=1012=(1001)(1.002011.00300 p100=1.0019(1.001)(1.104012)=1.105116
A concept is a category under which specific elements may be grouped.e.g. a red ball, a red pencil, and a red chair are all instances of the simple concept “red”. An “even number” is defined as any integer（整数） that is divisible by two without a remainder, and that an “odd number” is one that is not evenly(均匀地） divisible by two
