Gromov's systolic inequality for essential manifolds

Gromov's Systolic Inequality for Essential Manifolds is a mathematical idea about how certain shapes, called essential manifolds, are related to their areas. Essentially, Gromov's inequality states that for any essential manifold, the area of that manifold is no less than four times the length of its shortest closed path or loop. To understand this better, imagine a giant rubber sheet made up of a bunch of triangles, each triangle being an essential manifold. According to Gromov's inequality, the area of this rubber sheet can never be less than four times the length of the shortest closed path or loop possible on this rubber sheet.