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**1 - 1**of**1**### Extending Homomorphisms of Dense Projective Subplanes by Continuity

"... Let \Psi be a dense projective subplane of a topological projective plane \Pi. We show that a continuous homomorphism ff of \Psi is extendable to a continuous homomorphism of \Pi if and only if there is a line Z of \Psi such that the restriction of ff to the \Psi-points of Z is continuously exten ..."

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Let \Psi be a dense projective subplane of a topological projective plane \Pi. We show that a continuous homomorphism ff of \Psi is extendable to a continuous homomorphism of \Pi if and only if there is a line Z of \Psi such that the restriction of ff to the \Psi-points of Z is continuously extendable to some mapping defined on all \Pi-points of Z. In particular, each projective collineation of \Psi is extendable to a projective collineation of \Pi yielding the well-known result that (z; A)-transitivity of \Psi extends to (z; A)-transitivity of \Pi.