Let $M$ be a closed, triangulated manifold of dimension $m$ and $K(M)$ be its triangulation. Let $f\_i$ denote the number of $i$-simplices of $K(M)$. As proved by Klee the face numbers satisfy the following *Dehn-Sommerville* relations
$$ f\_k = \sum\_{i=k}^m (-1)^{i+m} \binom{i+1}{k+1} f\_i,$$
for $k = 0, 1, \dots, m$. 


The above formula holds true for more general spaces called the *semi-Eulerian complexes* (i.e., these are simplicial complexes such that the Euler characteristic of the link of every non-empty face is equal to that of an appropriate-dimensional sphere). 


Recall that the $h$-vector of a simplicial complex is defined as $h\_i = \sum\_{j=0}^i (-1)^{i-j} \binom{m-j}{m-i} f\_{j-1}$ for $0\leq i\leq m+1$. 
The Dehn-Sommerville relations have a particularly beautiful expression in terms of these $h$-vectors:
$$h\_{m+1-i} - h\_i = (-1)^i\binom{m}{i}(\chi(M) - \chi(S^m)) $$
for $0\leq i\leq m+1$. 


My question: Do these relations hold if one were to have a $\Delta$-complex (i.e., semi-simplicial complex) instead of simplicial triangulation of the manifold (one might have to assume the structure to be regular, i.e., attaching maps for homeomorphisms) ?


Is there an analogue of semi-Eulerian complex for $\Delta$-complexes ?



Dehn-Sommerville relations for $\Delta$-complexes
I think the answer is yes and the following is a sketch of proof:


* The second barycentric subdivision of a $\Delta$-complex is a triangulation.
* The f-vector of a $\Delta$-complex and of its barycentric subdivision are related by a matrix that preserves the Dehn-Sommerville relations.


