Real topological Hochschild homology and the Segal conjecture

We give a new proof, independent of Lin's theorem, the Segal conjecture for cyclic group order two. The key input is calculation, as Hopf algebroid, Real topological Hochschild homology F2. This determines E2-page descent spectral sequence map NF2?F2, where NF2 C2-equivariant Hill–Hopkins–Ravenel norm represents upper bound on RO(C2)-graded homotopy NF2, from which an immediate corollary.