Some remarks on robust features of surfaces in 4-space
Abstract
We study robust features of smooth surfaces in 4-space associated with contact with lines and hyperplanes. We investigate the local and multi-local singularities of orthogonal projections and height functions that describe these contacts and their corresponding geometric loci on the surface. At an A4-singularity of a height function, we show that the A3-curve and the A1A2-curve are generically tangent with contact of order $2$. We further establish criteria for the versality of the families of height functions and orthogonal projections in terms of the regularity of the B2-curve and S2-curve, respectively. Finally, we obtain the [A2]- and (A0S0)2-curves arising from multi-local singularities of orthogonal projections and describe their tangency properties at the B3- and H3-singularities.
Related
BibTeX
@misc{deolindosilva2026some,
title = {{Some remarks on robust features of surfaces in 4-space}},
author = {Jorge Luiz Deolindo-Silva},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40604},
eprint = {2610.40604},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40604},
}
RIS
TY - UNPB
TI - Some remarks on robust features of surfaces in 4-space
AU - Jorge Luiz Deolindo-Silva
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40604
UR - https://arxiv.org/abs/2610.40604
AB - We study robust features of smooth surfaces in 4-space associated with contact with lines and hyperplanes. We investigate the local and multi-local singularities of orthogonal projections and height functions that describe these contacts and their corresponding geometric loci on the surface. At an A_4-singularity of a height function, we show that the A_3-curve and the A_1A_2-curve are generically tangent with contact of order $2$. We further establish criteria for the versality of the families of height functions and orthogonal projections in terms of the regularity of the B_2-curve and S_2-curve, respectively. Finally, we obtain the [A_2]- and (A_0S_0)_2-curves arising from multi-local singularities of orthogonal projections and describe their tangency properties at the B_3- and H_3-singularities.
ER -