Index
$M$	Collection of manufacturers	$(1\cdots m\cdots M)$
$D$	Collection of distributors	$(1\cdots d\cdots D)$
$A$	Collection of disinfection and sterilization centers	$(1\cdots a\cdots A)$
$R$	Collection of stores	$(1\cdots r\cdots R)$
$C$	Collection of customer regions (Sales)	$(1\cdots c\cdots C)$
$J$	Collection of products	$(1\cdots j\cdots J)$
$V$	A set of modes of transport or a set of vehicles	$(1\cdots v\cdots V)$