FOR DIFFERENTIAL EQUATIONS OF FRACTIONAL ORDER

FOR DIFFERENTIAL EQUATIONS OF FRACTIONAL ORDER FOR DIFFERENTIAL EQUATIONS OF FRACTIONAL ORDER

12.07.2015 Views

42 T. S. Aleroev, H. T. Aleroeva, Ning-Ming Nie, and Yi-Fa TangNonlocal condition of conjugation set by the equation (2.5), and localboundary conditions (2.6), (2.7) coincide with Tricomi conditions. For λ =0, the problem (2.1) is an analogue of Tricomi type problem.From (2.5) and (2.8) for x = 0 and (2.7) for y = 0, it follows thatthe equality ϕ 0 (0) = ψ(0) is a necessary condition for the consistency ofboundary data.We have the following lemmaThenLemma 2.1. Let (2.3) be a solution of Problem 1τ(x) = u − (x, 0), ν(x) = ∂u−dy ∣ = 0; x −β ν(x) ∈ L[0, r].y=0τ ′′ (x) − λτ(x) = ν(x), (2.11)Γ(2β)D 1−2β0x τ(t) = [ β m ν(x) + x β D 1−β0x ψ(t)] Γ(β), (2.12)τ(0) = ϕ 0 (0),τ(r) − λwhere Γ(z) is Eulers gamma-function, andβ =m2m + 4 ,β m =∫ r0(r − t)τ(t) dt = ϕ r (0), (2.13)Γ(2 − 2βΓ(1 − β) (2 − 4β)2β−1 .In fact, as u = u + (x, y) is a solution of the problem (2.1) in the area Ω + ,from (2.2) by (2.4) we have u +′′ (x, 0) = ν(x). On the other hand, accordingto the nonlocal condition of conjunction (2.5) u +′′ (x, 0) = r ′′ (x) − λτ(x).From this equality the equality (2.10) follows between τ(x) and ν(x). Theequation (2.11) represents another form of the known equation of theoriesof the relation between τ(x) and ν(x) known from the theory of mixed typeequations, brought from the area Ω − to the line of parabolic degenerationfor Cellersted’s equations. The condition (2.13) is a consequence of (2.5)and (2.7).Excluding from the system (2.10)–(2.11), we havewhereL βτ(x) (x) = λτ + ψ β (x), (2.14)L βτ(x) (x) = τ ′′ (x) − µ β D 1−2β0x τ(t), (2.15)µ β = Γ(2β)β m Γ(β) , ψ β = − 1 x β D 1−β0x ψ(t). (2.16)β mHence, due to the condition of Lemma 2.1 the function τ(x) = u − (x, 0)should be a solution of the following nonlocal problem.Problem 2. Find a solution τ(x) of the equation (2.13) of classC 2 ]0, r[ ∩C 1 [0, r[ , satisfying the condition (2.12).

Boundary Value Problems for Differential Equations of Fractional Order 43Passing to investigation of structural and qualitative properties of thesolution of the Problem 2, we will notice that any solution of the equation(2.13) of the class C 2 ]0, r[ ∩C 1 [0, r[ ∩[0, r[ will be a solution of the equationτ(x) = τ ′ (0)x+τ(0)+µ β D −20x D1−2β 0tτ(ξ)+λD −20x τ(t)+D1−2β 0t ψ β (t). (2.17)The equation (2.16) is deduced from the equality (2.13) after applicationof the operator D 1−2β0t to both its parts.It is easy to see thatD0x −2 D1−2β 0tτ(ξ)=∫ x0(x−t) ∂ ∂t D−2β 0t τ(ξ) dt=D −10x D−2β 0tτ(ξ)=D −1In view of the latter from (2.16) by virtue of (2.12) we have0x D−2β 0tτ(t).ϕ r (0) − ϕ 0 (0) = rr ′ (0) + µ β D −1−2β0r τ(t) + D0r −2 ψ β(t). (2.18)Substituting the value of r ′ (0) (2.17) into the equation (2.16), we haveτ(x) = µ β D0x −α τ(t) + a 1xD0x −α τ(t) + λD−2 0x τ(t) + f 0(x), (2.19)where a 1 = −µ βr, α = 1 + 2β = 2(m + 1)/(m + 2),f β (x) = D −20x ψ β(t) + ϕ 0 (0) + x r[ϕr (0) − ϕ 0 (0) − D −20x ψ β(t) ] . (2.20)The equation (2.18) is an integral Fredholm’s equation of the secondkind and it is equivalent to Problem 1.2. Formulas for Calculation of Eigenvalues of a Boundary ValueProblemIntroduce some formulas from the theory of disturbance which we needin the further. Let T (χ, ε) be a linear operator bunch,T (χ, ε) = T + χT ′ + εT ′′ ,where T is a complete self-adjoined operator all eigenvalues of which areisolated and have multiplicity equal to 1; T ′ and T ′′ are defined in the sameHilbert space as T ; T is bounded.T (χ, ε) − ζ = T − ζ + χT ′ + εT ′′ = [ J + (χT ′ + εT ′′ )R(ζ, T ) ] (T − ζ)if ζ is not anigenvalue of T (χ, ε). Then, the resolventexists if the termR(ζ, x, ε) = R(ζ, T ) [ J − (χT ′ − εT ′′ )R(ζ, T ) ] −1[J − (χT ′ − εT ′′ )R(ζ, T ) ] −1may be determined as a Neumann’s series[J − (χT ′ − εT ′′ )R(ζ, T ) ] −1∑∞ [= − (χT ′ − εT ′′ )R(ζ, T ) ] n,n=0

Boundary Value Problems for Differential Equations of Fractional Order 43Passing to investigation of structural and qualitative properties of thesolution of the Problem 2, we will notice that any solution of the equation(2.13) of the class C 2 ]0, r[ ∩C 1 [0, r[ ∩[0, r[ will be a solution of the equationτ(x) = τ ′ (0)x+τ(0)+µ β D −20x D1−2β 0tτ(ξ)+λD −20x τ(t)+D1−2β 0t ψ β (t). (2.17)The equation (2.16) is deduced from the equality (2.13) after applicationof the operator D 1−2β0t to both its parts.It is easy to see thatD0x −2 D1−2β 0tτ(ξ)=∫ x0(x−t) ∂ ∂t D−2β 0t τ(ξ) dt=D −10x D−2β 0tτ(ξ)=D −1In view of the latter from (2.16) by virtue of (2.12) we have0x D−2β 0tτ(t).ϕ r (0) − ϕ 0 (0) = rr ′ (0) + µ β D −1−2β0r τ(t) + D0r −2 ψ β(t). (2.18)Substituting the value of r ′ (0) (2.17) into the equation (2.16), we haveτ(x) = µ β D0x −α τ(t) + a 1xD0x −α τ(t) + λD−2 0x τ(t) + f 0(x), (2.19)where a 1 = −µ βr, α = 1 + 2β = 2(m + 1)/(m + 2),f β (x) = D −20x ψ β(t) + ϕ 0 (0) + x r[ϕr (0) − ϕ 0 (0) − D −20x ψ β(t) ] . (2.20)The equation (2.18) is an integral Fredholm’s equation of the secondkind and it is equivalent to Problem 1.2. Formulas for Calculation of Eigenvalues of a Boundary ValueProblemIntroduce some formulas from the theory of disturbance which we needin the further. Let T (χ, ε) be a linear operator bunch,T (χ, ε) = T + χT ′ + εT ′′ ,where T is a complete self-adjoined operator all eigenvalues of which areisolated and have multiplicity equal to 1; T ′ and T ′′ are defined in the sameHilbert space as T ; T is bounded.T (χ, ε) − ζ = T − ζ + χT ′ + εT ′′ = [ J + (χT ′ + εT ′′ )R(ζ, T ) ] (T − ζ)if ζ is not anigenvalue of T (χ, ε). Then, the resolventexists if the termR(ζ, x, ε) = R(ζ, T ) [ J − (χT ′ − εT ′′ )R(ζ, T ) ] −1[J − (χT ′ − εT ′′ )R(ζ, T ) ] −1may be determined as a Neumann’s series[J − (χT ′ − εT ′′ )R(ζ, T ) ] −1∑∞ [= − (χT ′ − εT ′′ )R(ζ, T ) ] n,n=0

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