Consider the undirected graph $G=(V,E)$ example below. More precisely, the vertices in $V$ are labelled with $(x,y)$-coordinates and there is an edge between every vertices sharing the same $x$ and $y$ (not shown on the figure). For instance: $(1,1)-(1,2)$, $(1,1)-(1,3)$ and $(1,1)-(1,4)$
First question: Does this graph structure has a name? Note that the sketch is only an example and can be generalized, but I am not sure whether the generalized graphs would still be planar.
(1,1) --- (1,2) --- (1,3) --- (1,4)
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(2,1) --- (2,2) | |
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(3,1) --- (3,2) --- (3,3) --- (3,4)
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(4,1) --- (4,2)
Second question: I'm interested in finding short-cycle covers of this graph (length 4 or 6 typically). Two solutions of the problem for cycles of length 4 would be:
(1,1)-(1,2)-(2,1)-(2,2)
(3,1)-(3,2)-(4,1)-(4,2)
(1,3)-(1,4)-(3,3)-(3,4)
and
(1,1)-(1,3)-(3,1)-(3,3)
(1,2)-(1,4)-(3,2)-(3,4)
(2,1)-(2,2)-(4,1)-(4,2)
And one solution for cycles of length 6:
(1,1)-(2,1)-(2,2)-(3,2)-(3,4)-(1,4)
(1,2)-(1,3)-(3,3)-(3,1)-(4,1)-(4,2)
I know that the general case for 3-cycle cover is NP-complete, but does the special structure of this graph enables to get a simple algorithm solving the cycle cover problem?