University of Puerto Rico    (787) 764 0000

    Professor Information

    Valentin Keyantuo

    Address Department of Mathematics, 17 University Ave. Ste 1701
    San Juan PR, 00925-2537
    Office NCN II C-124
    Hours
    Actual Program
    Telephone (787) 764-0000 88270
    E-Mail ude.rpu@1outnayek.nitnelav

    Education

    PhD, Université de Franche-Comté, France., 1992

    Research Interests

    Análisis Funcional; Semigrupos de Operadores; Ecuaciones de Evolución; Ecuaciones Diferenciales Parciales

    Selected Publications

    1. V. Keyantuo, Omar El-Mennaoui and Ahmed Sani, Fractional integration of imaginary order in Hölder spaces. (Basel) Archiv Math., 120 (2023), 493-506.
    2. V. Keyantuo, Ernest Aragones and Mahamadi Warma, Approximate controllability of Hilfer type fractional differential equations. Vietnam J. Math., 49 (2021), 739-765.
    3. V. Keyantuo, Rafael Aparicio, Besov maximal regularity for a class of degenerate integro-differential equations with infinite delay in Banach spaces. Math. Methods Appl. Sci., 43 (2020), 7239-7268.
    4. V. Keyantuo, Rafael Aparicio, $L^p-$Maximal regularity for degenerate second order integro-differential equations on the real line. J. Fourier Anal. Appl., 26 (2020), paper No. 34, 39p.
    5. V. Keyantuo, Louis Tebou and Mahamadi Warma, A Gevrey class semigroup for a Thermoelastic plate model with a fractional Laplacian: Between the Euler-Bernoulli and Kirchhoff models. Discrete Contin. Dyn. Syst., 40 (2020), 2875-2889.
    6. V. Keyantuo, Fabian Seoanes and Mahamadi Warma, Fractional Gaussian estimates and holomorphy of semigroups., Archiv Math. (Basel) 113 (2019), 629-647.
    7. V. Keyantuo, Carlos Lizama, Silvia Rueda and Mahamadi Warma, Asymptotic behavior of mild solutions for a class of abstract nonlinear difference equations of convolution type. Adv. Difference Equ. 2019, Art. 251, 29 pp.
    8. V. Keyantuo, Y. Zelenyuk, Semigroup extensions of locally compact Abelian groups. Topology Appl. 263 (2019), 199-208.
    9. V. Keyantuo, Jorge González Camus, Carlos Lizama and Mahamadi Warma, Fundamental solutions for discrete dynamical systems involving the fractional Laplacian. Math. Methods Appl. Sci. 42 (2019) Paper No. 251, 29 pp.
    10. V. Keyantuo, Carlos Lizama and Mahamadi Warma, Lattice dynamical systems associated to a fractional Laplacian. , Numer. Funct. Anal. Optim. 40} (2019), no. 11, 1315-1343.
    11. V. Keyantuo, E. Álvarez, C. Gal and M. Warma, Well-posedness for a class of semilinear super-diffusive equations. Nonlinear Analysis, 181 (2019), 24-61.
    12. Keyantuo V., R. Aparicio, Well-posedness of a class of degenerate integro-differential equations in function spaces., Electronic J. Differential Equations, Vol. 2018 (2018), No. 79, pp. 1-31.
    13. (with C. Lizama and M. Warma) Existence, regularity and representation of solutions of fractional wave equations. Electronic J. Differential Equations, Vol. 2017 (2017), No. 222, pp. 142.
    14. (with Yevhen Zelenyuk) Right ideal decompositions of G∗. Topology and Applications. 210 (2016), 90-96.
    15. (with M. Warma) On the interior approximate controllability of fractional wave equations. Discrete Contin. Dyn. Syst. 36 (2016), no. 7, 3719-3739.
    16. (with C. Lizama and M. Warma) Existence, regularity and representation of solutions of fractional diffusion equations. Adv. Differential Equations 21 (2016), no. 9-10, 837-886.
    17. (with Y. Zelenyuk) Discrete subsets and convergent sequences in topological groups. Topology and Applications. 191 (2015), 137-142.
    18. (with C. Lizama and M. Warma) Spectral criteria for solvability of boundary value problems and positivity of solutions of time-fractional differential equations. Abstract and Applied Analysis, 2013, Art. ID 614328.
    19. (with P. J. Miana and L. S ́anchez Lajusticia) Sharp extension for convoluted solutions of abstract Cauchy problems. Integral Equations Op- erator Theory, 77 (2013), 211-241.
    20. (with Y. Zelenyuk) Strongly complete almost maximal left invariant topologies on groups. Topology and Applications, 160 (2013), 1494- 1500.
    21. (with C. Lizama and M. Warma) Asymptotic behavior of fractional order semilinear evolution equations. Differential Integral Equations, 26 (2013), 757-780.
    22. (with C. Lizama) On a connection between powers of operators and fractional Cauchy problems. Journal of Evolution Equations, 12 (2012), 245-265.
    23. (with C. Lizama) A characterization of periodic solutions for time- fractional differential equations in UMD spaces and applications. Math. Nachr. 284 (2011), 494-506.
    24. (with C. Lizama and P. J. Miana) Algebra homomorphisms defined via convoluted semigroups and cosine functions. J. Funct. Anal. 257 (2009), no. 11, 3454–3487.
    25. (with C. Lizama and V. Poblete) Periodic Solutions of Integro-differential Equations in Vector-valued Function Spaces. J. Differential Equations. 246 (2009), 1007-1037.
    26. (with R. Chill and M. Warma) Generation of cosine families on Lp(0, 1) by elliptic operators with Robin boundary conditions. In: H. Amann, W. Arendt, M. Hieber, F. Neubrander, S. Nicaise, J. von Below (Eds.): ”Functional Analysis and Evolution Equations - The Gunter Lumer Vol- ume”, 113-130, Birkh ̈auser, 2008.
    27. (with C. Lizama) Mild solutions of abstract differential equations. In: H. Amann, W. Arendt, M. Hieber, F. Neubrander, S. Nicaise, J. von Be- low (Eds.): ”Functional Analysis and Evolution Equations - The Gunter Lumer Volume”, 371-388, Birkh ̈auser, 2008.
    28. (with C. Lizama) H ̈older continuous solutions for integro-differential equations and maximal regularity. J. Differential Equations, 230(2006), 634-660.
    29. (with M. Warma)   The wave equation with Wentzell-Robin boundary conditions on Lp-spaces.J. Differential Equations, 229 (2006), 680-697.
    30. (with C. Lizama)  Periodic solutions of second order differential equations in Banach spaces. Math. Z. 253 (2006), 489-514.
    31. (with C. Müller and P. Vieten)  The Hille-Yosida theorem for local convoluted semigroups. Proc. Edinburgh Math. Soc.,46 (2003), 395-413.
    32. The Laplace transform and the ascent method for abstract wave equations. J. Differential Equations, 122 (1995), 27-47.
    33. (with W. Arendt and O. El-Mennaoui)  Local integrated semigroups: evolution with jumps of regularity. J. Math. Anal. Appl., 186 (1994), 572-595.

    Grants and Awards

    1. Co-PI: Air Force Office of Scientific Research [2014-2017]: Dynamics, Control and Numerics for Fractional Partial Differential Equations (PI: M. Warma).
    2. Convenio de Cooperaci ́on Internacional (CONICYT) Grant # 7060064 (Chile): 2006.
    3. Convenio de Cooperaci ́on Internacional (CONICYT) Grant # 7050008 (Chile): 2005.
    4. Convenio de Cooperaci ́on Internacional (CONICYT) Grant # 7010675 (Chile): 2002-2004.

    Additional Information

    Premio de Excelencia Academica, UPR Rio Piedras, 1999

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