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5 votes
1 answer
341 views

Which finite projective planes can have a symmetric incidence matrix?

As the title says. Which finite projective planes admit a symmetric incidence matrix? I am not an expert in the field at all, but I consulted with one. He claimed that $PG(2, \mathbb F_q)$ can always ...
11 votes
1 answer
269 views

Does every $C_4$-free bipartite graph lies in some finite projective plane?

A projective plane $Π$ is a 3-tuple $(P,L,I)$ where $P$ and $L$ are sets, and $I$ is a relation between $P$ and $L$, such that: For every two elements $p_1$, $p_2\in P$, there exists a unique ...
3 votes
0 answers
127 views

$\left< 15\right>^7/15$-womcode construction

In the article Womcodes constructed with projective geometries Frans Merkx constructed several good wom-codes (write-once memory codes, see How to reuse a "write-once" memory by Rivest & Shamir ...
9 votes
1 answer
399 views

Are bipartite Moore graphs Hamiltonian?

This is motivated by a computer-generated conjecture that bipartite distance-regular graphs are hamiltonian. I decided to check the case of Moore graphs first. The cycles and complete bipartite graphs ...
3 votes
0 answers
100 views

Applications of finite Bolyai-Lobachevsky planes

Google scholar gives more than 200 articles comcerning finite Bolyai-Lobachevsky (BL) planes. Usually they devoted to construction of such objects (axioms may be different). Are their any ...
5 votes
1 answer
140 views

Is there literature on finite geometries with ordered lines?

A difference between finite geometries and (e.g.) Euclidean space is that "lines" in finite geometries are unordered subsets of the universe, while "lines" in Euclidean space are ordered subsets of ...
12 votes
2 answers
820 views

Who constructed the projective plane of order $4$ from $K_6$?

I have been trying to hunt down the original reference for the construction of the projective plane of order $4$ from the complete graph on $6$ vertices. The reference I have at hand are Cameron and ...