  We investigate two constructive approaches to defining quasi-compact and
quasi-separated schemes (qcqs-schemes), namely qcqs-schemes as locally ringed
lattices and as functors from rings to sets. We work in Homotopy Type Theory
and Univalent Foundations, but reason informally. The main result is a
constructive and univalent proof that the two definitions coincide, giving an
equivalence between the respective categories of qcqs-schemes.
