Injective cochain map between the simplicial de Rham complex and the {C}ech-de Rham complex

For a class of simplicial geometries, we construct an open cover where each lower-dimensional simplex of codimension p is covered by an intersection of $p+1$ open sets in the open cover. We construct an injective cochain map from the simplicial de Rham complex to the {C}ech-de Rham complex of the open cover. Both the double complexes have coefficients in L², and the cochain map we construct is between the respective domain complexes. The image of the cochain map will be an embedding of the simplicial de Rham complex, realizing it as a subcomplex of the {C}ech-de Rham complex. The simplicial de Rham complex and the {C}ech-de Rham complex represent mixed-dimensional and equidimensional coupled problems, respectively.