q(x, t) ≤ 0
f2(x, t) ≥ 0
ГT = Г1 ∪ Г2,T = {(x, t): x ∈ , t = 0} ∪ {(x, t): x ∈ , 0 ≤ t ≤ T}
u(x, t) ≥