Other (mathematical) writings

2022

• A not-so-bad estimate of a locally uniform convergence. 

• The spectral theorem for operators on Hilbert spaces.*

2021

• A problem about divisibility.*

• Unofficial notes of Prof. K. R. Payne's course Advanced Topics in Real Analysis.* 

2020

• Notes on Lindelöf's μ and Riemann's ζ functions. 

• Unofficial notes of Prof. A. Gori's course Lie Groups.*

• Rolling triangles and hyperbolic dunes.*

2019

• A sufficient condition for the interior sphere property (with A. Felisi).

• The riddle of the candes. A problem about binary necklaces.

• A Phragmén—Lindelöf theorem.

• De monstris demersis. Why all functions are nowhere differentiable.*

• The circular execution. A problem about sliding numbers. 

2018

• The Hilbert transform as a limit of truncated integrals.

• On the isoperimetric inequality.*

• Hyperbolic cosine. Genesis of an exponential writing.*

• Two variations on the birthday problem.*

• On the value of the integral over R of 1/(1+x^2n)dx.*

• Solution to problem 24 of the team competition of Disfida Matematica '18.*

• On the maximum number of regions in which a polygon and its diagonals divide a circle. An example of the turkey illusion.*

• Satisfied pigeons and sinuous harmonics. A series with a dubious character (guided exercise and complete solution).*

• A complex proof of Ptolemy's theorem.

• On the minimal length of a cyclostyled multiple of a given integer.*

2017

• Exercises of arguable difficulty for a high school student.*

• On the solution of certain constant coefficient linear ODEs.*

• On the measure of the area below the graph of the function sin(x)/x.*

2016

• Solutions to Prof. C. Zanco's Exercises of Satisfaction (with F. Viganò).*

• Solutions to Prof. C. Zanco's Exercises of Some Interest.*

• A U.F.D. implies A[X] U.F.D.*

2015

• On the number of accumulation points contained in an uncountable subset of the Euclidean space (with F. Viganò).*

• On the number of proper k-subsets of non-consecutive integers in Z/nZ.*