Related papers: Comments on a Theorem by Ancona

I expound here in a more detailed way a proof of an important Serini's theorem, which I have already sketched in a previous Note. Two related questions are briefly discussed.

This note was written in Jan. 23, 2015 to answer a problem raised by G. Moser, who asked a constructive proof of a theorem by Ferreira-Zantema.

We present new proofs to four versions of Peano's Existence Theorem for ordinary differential equations and systems. We hope to have gained readability with respect to other usual proofs. We also intend to highlight some ideas due to Peano…

We propose several applications of an often overlooked part of the 1976 paper by Br\'ezis and Haraux, in which the Br\'ezis--Haraux theorem was established. Our results unify and extend various existing ones on the range of a linearly…

This note is the follow up to a paper by M. Waldschmidt.

In this note a characterization of anallytically Riesz operators is given. This work completes the article [1].

We collect here various conjectures on congruences made by the author in a series of papers, some of which involve binary quadratic forms and other advanced theories. Part A consists of 100 unsolved conjectures of the author while…

We give a new proof of an important theorem by Nakazi using recent results by Sarason in his seminal paper on agebraic properties of truncated Toeplitz operators.

Bianchi and Don\`{a} [1] have recently reported a proof to the variance formula of von Neumann entropy, which was conjectured in [2] and firstly proved in [3]. The purpose of this short note is to show that, despite having a different…

An technically interesting proof of a known theorem.

Letter/comment on M. Rini, Physics $\textbf{13}$, s94 (July 27, 2020) and A. Sanna et al., Phys. Rev. Lett. $\textbf{125}$, 057001 (2020).

We make a couple of remarks on ``Comments'' due to A. Moroz which were addressed to our recent letter "Differential cross section for Aharonov-Bohm effect with non standard boundary conditions", Europhys. Lett. 44 (1998) 403.

In this paper we prove an exponential covering lemma implying the three dimensional case of a well-known conjecture formulated by A. Zygmund circa 1935 and solved by A. C\'ordoba in 1978. Our approach avoids a subtle argument involving the…

New cases of the multiplicity conjecture are considered.

A short proof to a recent theorem of Giambruno and Mishchenko is given in this note.

In this expository paper we transcribe two letters by Guido Castelnuovo, one to Francesco Severi, the other to Beniamino Segre, and explain the contents of both, which basically focus on the quest for an algebraic proof of the equality…

This note (originally from 2015) provides a proof of a 1985 conjecture of Montiel and Ros concerning the conformal volume of tori. This updated version adds a proof of the claim made in Remark 5 about the value of the conformal volume of…

A concise presentation of Schrodinger's ancilla theorem (1936 Proc. Camb. Phil. Soc. 32, 446) and its several recent rediscoveries.

We point out a mistake in the statement of Corollary 2 in R. C. Alperin's paper on Selberg's lemma.

We give a new independent proof of a generalised version of the theorem by Rashevskii, which appeared in [Uch. Zapiski Ped. Inst. K. 2 (1938), 83 -- 94] and from which the classical Chow-Rashevskii Theorem follows as a corollary. The proof…