Searcharxiv⌕ Search

arXiv subjects

Luc Ramsès Talla Waffo

Publications and source records attributed to Luc Ramsès Talla Waffo.

9 recordsLinked to original sources

Compact Coefficient Formulae for Logarithmic Tangent and Hyperbolic Integrals

We develop compact coefficient-extraction formulae for several families of hyperbolic, logarithmic tangent, and Malmsten-type integrals whose values are finite linear combinations of odd zeta values and even Dirichlet beta values. The principal advantage of these formulae is that coefficients previously encoded by recursive arrays or nested finite sums are replaced by a single coefficient of an explicit elementary expression. This makes the coefficients easier to compute, keeps the dependence on the parameters visible, and reveals structural features---such as vanishing ranges, extremal coefficients, and sign patterns---without hidden cancellations. For shifted hyperbolic integrals with numerator $\sinh((2k+1)x)$, the coefficients are expressed through Chebyshev--arcsine extractions. The same mechanism yields Laurent coefficient formulae for logarithmic tangent integrals and leads to direct proofs of simple initial and terminal coefficients, including a parity-free terminal identity. For $m,n\geq1$, $m\geq n$, and $m+n$ even, we prove \[ \int_0^\infty\frac{\tanh^{m+1}x}{x^{n+1}}\,dx = (-1)^{(m-n)/2} \sum_{p=\lceil n/2\rceil}^{(m+n)/2} \binom{2p}{n} (2^{2p+1}-1) \frac{ζ(2p+1)}{π^{2p}} [u^{m+n-2p}](u\cot u)^{m+1}. \] \[\int_0^\infty \frac{\tanh^m x}{x^n\cosh x}\,dx = (-1)^{(m-n)/2} \sum_{p=\lceil n/2\rceil}^{(m+n)/2} 2^{2p}\binom{2p-1}{n-1} \frac{β(2p)}{π^{2p-1}} [u^{m+n-2p}] \frac{u}{\sin u}(u\cot u)^m \] In the diagonal zeta case, the formula gives the family $\int_0^\infty(\tanh x/x)^N\,dx$ in a direct, non-recursive form and makes the disappearance of the initial zeta values immediate.

math.GM↗

From Umbral Hyperbolic Integrals to a Cotangent Coefficient Formula for the Mittag Leffler Polynomials

Let \(g_n(x)\) be the Mittag--Leffler polynomials defined by $$ \sum_{n\ge0}g_n(x)t^n=\frac12\left(\frac{1+t}{1-t}\right)^x. $$ We derive the coefficient formula $$ g_n(x)=\frac1n\sum_{j=0}^{\lfloor (n-1)/2\rfloor} (-1)^j\frac{2^{n-2j-1}}{(n-2j-1)!} [u^{2j}](u\cot u)^n\,x^{n-2j}, $$ equivalently $$ [u^{n-r}](u\cot u)^n =(-1)^{(n-r)/2}\frac{n(r-1)!}{2^{r-1}}[x^r]g_n(x). $$ The identity is suggested by comparing an umbral representation of the hyperbolic tangent integral $$ K(a,b)=\int_0^\infty \frac{\tanh^a x}{x^b}\,dx $$ with a compact cotangent-coefficient formula, but is proved independently from the generating function by formal Lagrange--Bürmann inversion. Substitution of the proved bridge back into the integral formula then yields a rigorous derivation of the umbral Mittag--Leffler representation. We also develop a Dirichlet--beta analogue for $$ I_{m,n}^β=\int_0^\infty\frac{\tanh^m x}{x^n\cosh x}\,dx. $$ Defining \(q_m(x)\) by $$ \sum_{m\ge0}q_m(x)t^m=(1-t^2)^{-1/2}\exp(2x\operatorname{artanh}t), $$ we prove $$ [u^{m-r}]\frac{u}{\sin u}(u\cot u)^m =(-1)^{(m-r)/2}\frac{r!}{2^r}[x^r]q_m(x). $$ This gives a parallel umbral representation for the beta integrals. The family \(q_m\) is a shifted \(c=-1,β=1\) specialization of the classical Meixner family, yielding a beta/Meixner counterpart to the zeta/Mittag--Leffler correspondence.

math.GM↗

Dirichlet Beta Analogues, Sign Alternation, and Lerch Unification of Hyperbolic and Logarithmic Tangent Integrals

We develop a Dirichlet-beta counterpart and a structural extension of the coefficient-extraction framework for hyperbolic and logarithmic tangent integrals. For integers $m\geq n\geq1$ with $m+n$ even, the zeta-type formula \[ \int_0^\infty\frac{\tanh^{m+1}x}{x^{n+1}}\,dx = (-1)^{(m-n)/2} \sum_{p=\lceil n/2\rceil}^{(m+n)/2} \binom{2p}{n}(2^{2p+1}-1) \frac{ζ(2p+1)}{π^{2p}} [u^{m+n-2p}](u\cot u)^{m+1} \] admits the beta-type analogue \[ \int_0^\infty \frac{\tanh^m x}{x^n\cosh x}\,dx = (-1)^{(m-n)/2} \sum_{p=\lceil n/2\rceil}^{(m+n)/2} 2^{2p}\binom{2p-1}{n-1} \frac{β(2p)}{π^{2p-1}} [u^{m+n-2p}] \frac{u}{\sin u}(u\cot u)^m. \] The proof uses derivative polynomials, a beta kernel, and a coefficient-collapse argument. We then establish strict sign alternation for several coefficient families. In the boundary shifted-hyperbolic case the sign is controlled by generalized Bernoulli polynomials, while the arctanh and logarithmic tangent families are identified with continuous dual Hahn and continuous Hahn polynomials. Their zero distributions turn the observed alternation into structural statements valid for all admissible indices. Finally, with $λ(s)=(1-2^{-s})ζ(s)$, we show that the parallel zeta--lambda and beta identities are the two binary specializations of a single Lerch-transcendent scheme with $\varepsilon\in\{0,1\}$. The same convention $\varepsilon=0$ for the beta case and $\varepsilon=1$ for the zeta--lambda case is used throughout. Besides the shifted hyperbolic, odd-$\sinh$, logarithmic tangent, and $\tanh$ families, this framework yields a further unified pair of reciprocal-arctanh integral formulae on $(0,1)$.

math.GM↗

Right edge rates of the zeros of $\widetildeΞ_n$ and $\widetildeΛ_n$

We consider the two families of even polynomials $Ξ_n$ and $Λ_n$ studied in~\cite{TallaWaffo2026arxiv2602.16761}, together with the rescaled polynomials $\widetildeΞ_n(x):=Ξ_n(\sqrt{x})$ and $\widetildeΛ_n(x):=Λ_n(\sqrt{x})$, $n\ge2$. Their zeros are real, simple, and contained in $(0,1)$. Writing them as $0<x^{(Ξ)}_{1,n}<\cdots<x^{(Ξ)}_{n-1,n}<1$ and $0<x^{(Λ)}_{1,n}<\cdots<x^{(Λ)}_{n-1,n}<1$, we study the asymptotic behaviour of the largest zeros $x^{(Ξ)}_{n-1,n}$ and $x^{(Λ)}_{n-1,n}$. We prove that the two families have different exponential rates at the right endpoint: \[ \frac{1}{n-1}\log\bigl(1-x^{(Λ)}_{n-1,n}\bigr)\to-\log4, \qquad \frac{1}{n-1}\log\bigl(1-x^{(Ξ)}_{n-1,n}\bigr)\to-\log9. \] Thus, although the two families share the same global limiting zero distribution, their extreme right zeros approach $1$ on different exponential scales. The proof is based on the representation of $Ξ_n$ and $Λ_n$ in terms of Eulerian polynomials of type~B and type~A, respectively, and on an elementary estimate for the smallest negative zero in terms of the first non-constant coefficient.

math.GM↗

Structure and Zero Asymptotics of Differential Operators Associated with $Ξ_n$ and $Λ_n$

We study the second-order differential operators \(\mathcal D_Ξ\) and \(\mathcal D_Λ\) associated with the rescaled polynomial families \((\widetildeΞ_n)\) and \((\widetildeΛ_n)\), and more generally the polynomial sequences generated by iterating these operators from an arbitrary linear initial datum \(cx-d\). We establish structural properties of \(\mathcal D_Ξ\) and \(\mathcal D_Λ\), including factorizations into first-order operators, weighted divergence forms, formal self-adjointness, and hypergeometric descriptions of the corresponding formal eigenvalue equations. We also show that both operators preserve hyperbolicity, preserve zeros in \((0,b)\) for \(b\ge 1\), and preserve proper position. For the iterated polynomial sequences, we derive explicit closed formulae in terms of the auxiliary families \((\widetildeΞ_n)\) and \((\widetildeΛ_n)\), prove strict interlacing of consecutive zeros under explicit conditions on \(d/c\), and obtain asymptotic formulae for the normalized logarithmic derivatives. As a consequence, the associated zero counting measures converge weakly to the same limiting probability measure as in the auxiliary case.

math.GM↗

Algebraic representatives of the ratios $ζ(2n+1)/π^{2n}$ and $β(2n)/π^{2n-1}$

In \cite{TallaWaffo2025arxiv2511.02843} we introduced even polynomials $Ξ_n,Λ_n\in\mathbb{Q}[x]$ arising from integral representations of $β(2n)/π^{2n-1}$ and $ζ(2n+1)/π^{2n}$. In this paper we give explicit closed formulae for these polynomials in terms of Eulerian numbers and study their structural properties. These properties may prove useful in studies on the arithmetic nature of the ratios $β(2n)/π^{2n}$ and $ζ(2n+1)/π^{2n+1}.$

math.NT↗

Asymptotic zero distribution of the polynomials $\widetildeΞ_n$

We consider the polynomials $Ξ_n$ introduced in~\cite{TallaWaffo2025arxiv2511.02843} and studied in further details in\cite{TallaWaffo2026arxiv2602.16761}, which are expressed in terms of Eulerian polynomials of type~B, and study the zero distribution of the rescaled family \[ \widetildeΞ_n(x) := Ξ_n(\sqrt{x}), \qquad n\ge 2. \] Writing the zeros of $\widetildeΞ_n$ in the interval $(0,1)$ as $0< x_{n,1} \le \cdots \le x_{n,n-1} < 1$ and forming the empirical measures \[ μ_n := \frac1{n-1}\sum_{k=1}^{n-1}δ_{x_{n,k}}, \] we prove that $(μ_n)_{n\ge2}$ converges weakly to a deterministic probability measure $μ$ supported on $(0,1)$. We give an explicit formula for the limiting density and the limiting distribution function of~$μ$. The proof is based on a representation of $Ξ_n$ in terms of type~B Eulerian polynomials, a ratio asymptotic for these polynomials derived from a classical series identity, and the Stieltjes transform method. We also provide numerical experiments illustrating the convergence of the empirical zero distributions to~$μ$.

math.GM↗

Perspectives on the arithmetic nature of the ratios $ζ(2n + 1)/π^{2n+1}$ and $β(2n)/π^{2n}$

We investigate the values of the Riemann zeta function at odd integers and the Dirichlet beta function at even integers, by collecting several distinct analytic frameworks converging to these values, thus providing a unifying perspective. Beyond analytic interest, these formulas motivate linear independence conjectures which, if established, would imply the irrationality of the quantities $ζ(2n + 1)/π^{2n+1}$ and $β(2n)/π^{2n}$

math.NT↗

The Mellin's transforms of $\dfrac{1}{\operatorname{arctanh} x}$ and $\dfrac{1}{\sqrt{1-x^2}\,\operatorname{arctanh} x}$

We investigate the Mellin transforms of \(1/\operatorname{arctanh} x\) and \(1/(\sqrt{1-x^{2}}\,\operatorname{arctanh} x)\), viewed as compactly supported functions on \((0,1)\). These transforms are closely connected with conjectures on the arithmetic nature of the ratios \(ζ(2n+1)/π^{2n+1}\) and \(β(2n)/π^{2n}\). While their values at odd integers were previously studied, the evaluation at even integers leads to classes of improper integrals that cannot be handled by parity arguments. Using contour integration techniques, we derive explicit closed-form expressions involving derivatives of the Riemann zeta and Dirichlet beta functions, thereby extending earlier results and providing new analytic tools for the study of related hyperbolic integrals.

math.NT↗