关于一个定义的解释，请求帮忙！

skysophie

Definitions.-An arrangement of v objects (called treatments) in b sets
8 Q. ^: U; f8 g(called blocks) will be called a pairwise balanced design of index unity and type
# M+ _% j$ a' V4 w: i1 Z* o$ ^1 _(v; ki, k2, .. ., ki) if each block contains either k1, k2, .. ., or km treatments which
- A3 k7 H8 R1 l7 }7 Eare all distinct (k, < v, k, $ kj), and every pair of distinct treatments occurs exactly
& Z3 P" y2 y# w8 l& X6 A0 }in one block of the design. If the number of blocks containing k, treatments is
: z/ o. a+ e* Ib,, then clearly  b = A bi, v(v-1) = i biki(k -1)。。。
6 i/ l  C. s  M* i5 K$ m' g" a
谁能帮我解释一下，可以举个简单的例子。。谢谢！~

角凳

是告诉我们这是哪个领域的么？？