On the Diffusion of Waves and the Lacunas for Hyperbolic Equations*
O A Oleĭnik · 2023
Consider the following equation ( 1 ) https://www.w3.org/1998/Math/MathML" display="block"> ∂ 2 u ∂ t 2 = ∑ k = 1 p ∂ 2 u ∂ x k 2 , https://www.w3.org/1999/xlink" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003421535/30023ac0-3f0f-4fea-8919-69439612d9a8/content/eq2795.tif "/>