η

:

Demand coefficient

γ

:

Demand constant

p

:

Selling-price

T

:

Duration of cycle

r

:

Discount rate which represents time value of money

i

:

Inflation rate per unit time

C_HC

:

Holding cost

C_PC

:

Production cost

C_DC

:

Deterioration cost

A

:

Setup cost

Q₁

:

Maximum inventory level at time t₁

Q₂

:

Maximum inventory level at time t₂

Q₃

:

Maximum inventory level at time t_d

I₁(t)

:

Inventory level, at any time t, during [0, t₁]

I ₂(t)

:

Inventory level, at any time t, during [t₁, t₂]

I ₃(t)

:

Inventory level, at any time t, during [t₂, t_d]

I ₄(t)

:

Inventory level, at any time t, during [t_d, T]

TC(T)

:

Total inventory cost

${\tilde{C}}_{HC}$

:

Fuzzy holding cost

${\tilde{C}}_{DC}$

:

Fuzzy deterioration cost

${\tilde{C}}_{PC}$

:

Fuzzy production cost

$\tilde{A}$

:

Fuzzy Setup cost