I don't understand this material :( Could anyone help please? Or at least recommend a good book on this sort of material so that I could go and read it (& hope fore some quick enlightenment before my final)
For instance this is a exercise out of our text book that our prof said we should be capable of doing ... I tried it and ended up with something very wrong. As I said at the start of this post, I don't understand this material ... I like the recurrence relations better.
In any event here is the qn:
It says if t >= 2, a t-(b,v,r,k,lamda) -design consists of a set X of v >= 2 varieties, & a collection of b>0 subsets of X called blocks, such that each block consists of exactly the same # k of varieties, k>0, & each variety appears in exactly the same # r of blocks, r>0, such that every t-element subset of X is a subset of exactly lamda blocks, lamda>0, & such that k<v. Obviously, a 2-2-(b,v,r,k,lamda) -design is a (b,v,r,k,lamda)-design.
Now the qn part asks us to suppose that x_(i_1), x_(i_2), ..., x_(i_t) are t distinct varieties of a t-(b,v,r,k,lamda) -design. For 1=<j=<t let lamda_j be the number of blocks containing x_(i_1), x_(i_2), ..., x_(i_j). Let lamda_0 = b. Show that for 0=<j=<t,