杰弗瑞.杰尼和菲利普.瑞尼的高微,博弈论定理7.1,看不懂,THEOREM7.1SimplifiedNashEquilibriumTestsThefollowingstatementsareequivalent:(a)mˆ∈MisaNashequilibrium.(b)Foreveryplayeri,ui(mˆ)=ui(si,mˆ

Question

杰弗瑞.杰尼和菲利普.瑞尼的高微,博弈论定理7.1,看不懂,
THEOREM 7.1 Simplified Nash Equilibrium Tests
The following statements are equivalent:
(a) mˆ ∈ M is a Nash equilibrium.
(b) For every player i,ui(mˆ ) = ui(si,mˆ −i) for every si ∈ Si given positive weight by
mˆ i,and ui(mˆ ) ≥ ui(si,mˆ −i) for every si ∈ Si given zero weight by mˆ i.
(c) For every player i,ui(mˆ ) ≥ ui(si,mˆ −i) for every si ∈ Si.
positive weight是什么意思啊,zero weight又是什么意思；后面的例题说“运用定理（b)部分每个局中人必定会对其每种纯对策无差异”这句话又是怎么理解?

Answer 1

ZERO WEIGHT 即加起来为零,这只的是零和博弈,即一方胜利一方失败,加起,来的效用为零