arXiv subjects

Antti Hippeläinen

Publications and source records attributed to Antti Hippeläinen.

4 recordsLinked to original sources

arXiv2026

Measuring inequality and social stratification with Lorenz curvature

We construct a continuous family of inequality and social stratification indices based on the curvature of the Lorenz curve. We study the inequality axioms of the family and find that they are satisfied only with the so-called stratification-aversion parameter $α$ set to 0 -- in all other cases, these constraints cannot be satisfied in a strict sense. With $α= 0$, the index has a very simple closed form and its value can be easily approximated. We study the values of the index on World Bank inequality data and see how the rankings across a wide selection of countries change as $α$ is varied. Spearman and Kendall rank-correlation matrices with other common indices are also computed and analyzed. We find the curvature index to deviate consistently from the comparison indices, albeit less so for consumption- than income-based countries.

econ.GN↗

arXiv2026

Formalization of the generalized Pareto principle and structural typicality of the 20/80-rule

We formalize a generalized form of the Pareto principle - ``fraction $p$ of inputs yields fraction $1-p$ of outputs'' - as a property of non-negative gain densities $\ell \in L^1([0,1])$, working with the decreasing rearrangement to obtain a unique characterization. For probability distributions, the resulting $p$ coincides with $1 - k_F$, where $k_F$ is the Kolkata index of the corresponding Lorenz curve. Within this framework we analyze both constructed gain densities and commonly encountered distribution families. We derive closed-form expressions for $p$ for truncated power-law, exponential, and normal distribution families. Combining these with estimates of the truncation parameter as a function of sample size $N$, we predict that datasets of size $N \in [10^2, 10^5]$ from exponential and normal families concentrate $p$ near $[0.15, 0.26]$ and $[0.20, 0.29]$ - values close to the canonical 0.2/0.8-rule, and strictly below the saturation $k \approx 0.865$ conjectured earlier by Ghosh and Chakrabarti. We discuss the implications of the structural ubiquity of Pareto-type imbalances for their use as prescriptive targets.

physics.soc-ph↗

arXiv2026

Gravitational form factors of the proton in the improved holographic QCD model

We compute the gluonic contribution to the gravitational form factors of the proton using the improved holographic QCD model, in which the proton is described in terms of bulk Dirac fermions. Model parameters are constrained using lattice and phenomenological input, allowing us to obtain estimates for the gravitational form factors and to compare them with results from other approaches. The resulting gluonic contribution to the $\mathcal{D}(t)$ form factor is found to exhibit an infrared pole in our framework. Using the extracted form factors, we analyze mechanical properties of the proton, including pressure and shear distributions. We obtain estimates of $ρ_{\text{mech}} = 0.95$ fm and $ρ_{\text{mass}} = 0.61$ fm for the mechanical and the mass radii of the proton, respectively, which are similar to other nonperturbative studies.

hep-th↗

arXiv2022

Higgs phases at non-zero density from holography

We show how Higgs phases at non-zero density can be described using a simple analytic method for gauge theories possessing a holographic dual. We introduce co-dimension one branes in a bottom-up gravity dual that are sources of form flux, such that the effective curvature radius is changed when the brane is crossed. This mimics the expected flow produced by color branes nucleating in a top-down model.

hep-th↗