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    Berkeley preliminary exam Fall 1983

    SRC-BERKELEY-PRELIM-FALL-1983

    Area
    Prelim
    Status
    draft
    Source

    20 problems.

    1. Fourier transform of \(\operatorname{sech}^2x\)
    2. No surjective ring homomorphism \(M_{n+1}(F)\to M_n(F)\)
    3. Bounded partial derivatives allow a punctured-space function to extend continuously
    4. Every real sequence has a monotone subsequence
    5. Spectrum and determinant of the matrix with zero diagonal and ones off diagonal — Fall 1983 Problem 5; repeated exactly as Spring 1996 Problem 16
    6. Zeros of \(z^5+z^3+5z^2+2\) in \(1<|z|<2\)
    7. If \(G\times G\) has exactly four normal subgroups then \(G\) is simple nonabelian
    8. Symmetric orthogonal transformations of \(\RR^3\)
    9. Parameters yielding infinitely many critical points for a forced second-order ODE
    10. Uniform continuity plus convergence of an improper integral forces decay to zero
    11. A converse to l’Hopital’s rule need not hold
    12. Partial fractions for a rational function with distinct simple poles
    13. Scalar and vector exponential-growth inequalities
    14. Commuting diagonalizable matrices are simultaneously diagonalizable — Fall 1983 Problem 14; commuting diagonalizable operators are simultaneously diagonalizable
    15. Holomorphic functions real on the unit circle
    16. Derivative of \(\operatorname{tr}(F(t)^3)\)
    17. Finite integral domains are fields — Fall 1983 Problem 17; every finite integral domain is a field
    18. Implicit solution of \(f(x)=t g(x)\) near a simple zero of \(f\)
    19. Irreducibility of \((x^p-1)/(x-1)\) over \(\QQ\) — Fall 1983 Problem 19; prime cyclotomic polynomial is irreducible
    20. Full-rank rectangular matrices form an open set with a continuous left inverse