3.1-8

题目有点问题，c不应该是整数
$\Omega(g(n,m))=\{f(n,m):\exists c>0，正整数n_0和m_0,使得对所有的n\geq n_0,m\geq m_0$
$有0\leq cg(n,m)\leq f(n,m)\}$
$\Theta(g(n,m))=\{f(n,m):\exists c_1>0,c_2>0，正整数n_0和m_0,使得对所有的n\geq n_0,m\geq m_0$
$有0\leq c_1g(n,m)\leq f(n,m) \leq c_2g(n,m)\}$