Geodesic
On Relative Widths of Classes of Differentiable Functions
Trudy Matematicheskogo Instituta imeni V.A. Steklova, Studies on function theory and differential equations, Tome 248 (2005), pp. 250-261 
Yu. N. Subbotin; S. A. Telyakovskii. On Relative Widths of Classes of Differentiable Functions. Trudy Matematicheskogo Instituta imeni V.A. Steklova, Studies on function theory and differential equations, Tome 248 (2005), pp. 250-261. http://geodesic.mathdoc.fr/item/TM_2005_248_a22/
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     title = {On {Relative} {Widths} of {Classes} of {Differentiable} {Functions}},
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Voir la notice du chapitre de livre provenant de la source Math-Net.Ru

The Kolmogorov widths $d_{2n} (W^r_C, C)$ and relative widths $K_{2n}(W^r_C,MW^j_C,C)$ of the class $W^r_C$ with respect to $MW^j_C$, where $j r$, are considered. The minimal multiplier $M$ for which these widths are equal is estimated from above and below; the bounds obtained show that this minimal value is asymptotically equal to the Favard constant $\mathcal K_{r-j}$ as $n \to \infty $.

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