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• Article
Katz, Daniel J.
Consider the Weil sum , where is a finite field of characteristic , is the canonical additive character of , is coprime to , and . We say that is three-valued when it assumes precisely three distinct values as runs through : this is the minimum number . . .
• Article
Fuller, Terry
We show that there are homeomorphisms of closed oriented genus surfaces which are fiber-preserving with respect to an irregular branched covering and isotopic to the identity, but which are not fiber-isotopic to the identity.
• Article
Sivic, Klemen
We show that for all $k\ge 1$ there exists an integer $N(k)$ such that for all $n\ge N(k)$ the $k$-th order jet scheme over the commuting $n\times n$ matrix pairs scheme is reducible. At the other end of the spectrum, it is known that for all \$ k . . .
• Article
Stevenson, Katherine F.
Recently, it has been shown by Harbater and Stevenson that a profinite group G is free profinite of infinite rank m if and only if G is projective and m-quasifree. The latter condition requires the existence of m distinct solutions to certain embeddin . . .
• Article
Harbater, David
We study the properties of the fundamental group of an affine curve over an algebraically closed field of characteristic p from the point of view of embedding problems. In characteristic zero the fundamental group is free, but in characteristic p it i . . .
• Article
Sethuraman, Bharath
Let n = pab ,w here pis a prime, and g.c.d. (p;b )=1 . In P n 2 1 , let Xr be the variety dened by rank ((xi;j)) n r. We show that any subvariety of Xr of codimension less than par must have degree a multiple of p. We also show that the bounds on the . . .
• Article
Candel, Alberto
This paper gives an upper bound for the first eigenvalue of the universal cover of a complete, stable minimal surface in hyperbolic space, and a sharper one for least area disks.
• Article
D'Orsogna, Maria-Rita R.
We introduce a two-variable lattice model to describe conflict within communities. Our model includes polarization and radicalization of individuals, each of which harbors a continuous belief variable and a discrete radicalization level describing the . . .
• Article
Li, Yi Li
For a class of two-point boundary value problems we prove exactness of an S-shaped bifurcation curve. Our result applies to a problem from combustion theory, which involves nonlinearities like for [formula].
• Conference paper or proceedings
Li, Yi Li
We study the stability and exact multiplicity of periodic solutions of the Duffing equation with cubic nonlinearities. We obtain sharp bounds for h such that the equation has exactly three ordered T-periodic solutions. Moreover, when h is within these . . .