ELVAE: Evidential Learning-Based Variational Autoencoder for Uncertainty-Aware Generation

ELVAE places an input-dependent normal–inverse-gamma (NIG) hierarchy at each VAE latent coordinate, separating location uncertainty $u_{\mathrm{e}\mathrm{p}\mathrm{i}}=\beta \mathrm{/}[\nu (\alpha -1)]$ from conditional variability $u_{\mathrm{v}\mathrm{a}\mathrm{r}}=\beta \mathrm{/}(\alpha -1)$. The marginalized latent law, however, identifies only the three quotient coordinates $(\gamma ,\alpha ,c)$ with $c=\beta (1+1\mathrm{/}\nu )$; reconstruction is blind to one $(\nu ,\beta )$ fiber direction. A companion theoretical analysis shows that the complete NIG prior and forward KL select a unique prior-relative canonical representative on each fiber, so canonical inverse allocation is not a fourth independent information channel. Empirically, trained inverse evidence $1\mathrm{/}\nu$ remains the strongest sensitivity-ranking score. At ${\tau }_{\mathrm{e}\mathrm{p}\mathrm{i}}=1$, the three-seed mean high/low-$u_{\mathrm{e}\mathrm{p}\mathrm{i}}$ semantic-transition ratios are 1.98 on MNIST and 1.66 on Fashion-MNIST, falling to 1.33 and 1.16 under scale-matched controls. In the 20-draw MNIST component study with equal per-anchor perturbation energy, $1\mathrm{/}\nu$ gives high/low ratios 1.69 and 1.65 under the $u_{\mathrm{e}\mathrm{p}\mathrm{i}}$ and $u_{\mathrm{v}\mathrm{a}\mathrm{r}}$ fields and 1.69 (95% interval 1.45–1.97) under a geometry-free isotropic field, whereas $u_{\mathrm{v}\mathrm{a}\mathrm{r}}$ reverses the isotropic ordering to 0.76. Under the experimental prior, canonical $1\mathrm{/}{\nu }_{\mathrm{c}\mathrm{a}\mathrm{n}}$ is a strictly increasing transform of $T=c\mathrm{/}[\alpha ({\gamma }^2+2)]$ and is bounded above by $3+\sqrt{10}$. Thus ELVAE exposes a controllable sensitivity mechanism whose trained four-output realization is operationally informative, while the exact reconstruction-visible information remains three-dimensional and baseline image quality is a separate question.