## Related pagesIsomorphisms of partial linear spacesIsomorphisms of linear spaces Isomorphisms of projective planes |

with

Two incidence structures are isomorphic if there exists an isomorphism from to . An isomorphism respects point rows and line pencils, i.e.

for all points p and all lines l.

Obviously, the set of all automorphisms of an incidence structure is a subgroup of the group

called the automorphism group of .

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