18 problems.
- A convergent sequence together with its limit is compact
- Homomorphisms from \((\mathbb Q,+)\) to the positive rationals under multiplication
- Region of convergence of an exponential series in the complex plane
- The map \(X\mapsto AXB\) from \(n\times m\) to \(m\times n\) matrices is not invertible for \(m\ne n\)
- Zeros at \(0\) and \(1\) force zeros at every integer for a constant-coefficient ODE
- Cancellation for direct products of finite abelian groups
- Critical points of the determinant map on real matrices
- A complex matrix of finite order is diagonalizable
- The integral \(\int_{-\infty}^{\infty} e^{-ix}/(x^2-2x+4)\,dx\)
- The cluster set at infinity of a continuous real function is an interval
- A finite subgroup of the unit group of an integral domain is cyclic
- Winding-number formula for \(\frac1{2\pi i}\int_\gamma e^z z^{-2}(1-z^2)^{-1}\,dz\)
- At least two nonisomorphic nonabelian groups of order \(40\)
- Positive initial data for \(f'=f^n\) on \([0,\infty)\)
- A symmetric \(4\times4\) matrix has signature \((2,2)\)
- Equicontinuity of an integral-operator image of the unit ball
- Weighted orthonormal polynomial basis with \(\langle p_k,p_k'\rangle=0\)
- The cosine transform of a continuous function is entire and injective