, . apc aps , : , , . 1:
apc + aps = 1.
(I = S) :
: C = C 0 + mpc × ,
: S = C 0 + mps × ,
: I = I 0 k × R + MPI × ,
C 0 ( );
( C 0) ( , );
I 0 , ;
k ;
R ;
(I 0 k × R) ;
MPI , .
2.2 , . 2.3 , .
.
. , () () . , , .. , , .
,
Δ ,
Δ AD .
: , .
.
2.4 .
AD AS .
2.5 2.6 , AD AS .