Question 1
For example for: $$ \bigvee_{i = 7}^{9} p_{i} $$
we write: $$ \bigvee_{i = 7}^{9} p_{i} = p_{7}\vee p_{8}\vee p_{9} $$
What we write for? $$\bigwedge_{i=1}^{9} \bigwedge_{n=1}^{9} \bigvee_{j=1}^{9}~p(i,j,n)$$
Question 2
What is called that form?
$$ \bigvee_{i = 7}^{9} p_{i} $$
And what is called that form?
$$ p_{7}\vee p_{8}\vee p_{9} $$
\begin{equation} \bigwedge_{i=1}^{2} \bigwedge_{n=1}^{2} \bigvee_{j=1}^{2}~p(i,j,n)=\\ =\left(\bigwedge_{n=1}^{2} \bigvee_{j=1}^{2}\ p(1,j,n)\right) \wedge \left(\bigwedge_{n=1}^{2} \bigvee_{j=1}^{2}\ p(2,j,n)\right)=\\ =\left[\left(\bigvee_{j=1}^{2}\ p(1,j,1)\wedge \bigvee_{j=1}^{2}\ p(1,j,2)\right)\right] \wedge \left[\left( \bigvee_{j=1}^{2}\ p(2,j,1)\wedge \bigvee_{j=1}^{2}\ p(2,j,2)\right)\right]=\\ =(p(1,1,1)\vee p(1,2,1))\wedge (p(1,1,2)\vee p(1,2,2))\wedge (p(2,1,1)\vee p(2,2,1))\wedge (p(2,1,2)\vee p(2,2,2)) \end{equation}
This is the compact form: $$\bigvee_{i=7}^{9}p_i$$
This is the expanded form: $$p_7\vee p_8\vee p_9$$