Status
On this page
Status
Topics
Status
On this page
Status
Topics
We say that is an essential component if for every with where is the Schnirelmann density.
Can a lacunary set be an essential component?
Source: erdosproblems.com/37
An accepted solution exists. The statement is false.
DISPROVED (LEAN), the site's label; its suffix is a catalog
label explained under Formalization. The status-defining source is Ruzsa's
theorem (Proc. London Math. Soc. (3) 54 (1987), 38--56, refereed): an
essential component satisfies
for some and
all large , while a lacunary set has only elements up to ,
so the answer is no. The claim page is
Ruzsa,
accepted on the site curator's credit and the refereed publication; the
2026 Lean development that declares itself a formalization of his theorem
is linked there and gives no formalized evidence, since this corpus has
not built or audited it.