We formulate the functional differential problem. Let a > 0, r0 ∈ R+ b = (b1,…, b n ) ∈ R n and r = (r1,…, r n ) ∈ R + n be given where b i > 0 for 1 ≤ i ≤ n. Suppose that κ ∈ Z, 0 ≤ κ ≤ n, is fixed. For each y = (y1,…,y n ) ∈ R n we write y = (y′,y″) where y′ = (y1,…,y″), y″ = (y κ +1,…,y n ). We have y′ = y if κ = n and y″ = y if κ = 0. We define the sets $$ E = \left( {0,\,a} \right) \times \left[ { - b',\,b'} \right) \times \left( { - b'',\,b''} \right],\;B = \left[ { - {r_0},\,0} \right] \times \left[ {0,\,r'} \right] \times \left[ { - r'',\,0} \right]. $$