Интегрируемость и бесконечные иерархии симметрий и законов сохранения

Integrable differential equations (no matter what definition of integrability is used) have infinite hierarchies of symmetries and/or conservation laws. We present wide classes of PDE also possessing infinite series of nonlocal symmetries or conservation laws. For example, any nontrivial conservation law of an l-normal PDE generates an infinite family of nonlocal conservation laws. The results are obtained within the framework of nonlocal theory of PDE.