Geodesic
Examples of quasitopological groups
Buletinul Academiei de Ştiinţe a Republicii Moldova. Matematica, no. 2 (2013), pp. 111-118 
Alexander V. Arhangel'skii; Mitrofan M. Choban. Examples of quasitopological groups. Buletinul Academiei de Ştiinţe a Republicii Moldova. Matematica, no. 2 (2013), pp. 111-118. http://geodesic.mathdoc.fr/item/BASM_2013_2_a12/
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Voir la notice de l'article provenant de la source Math-Net.Ru

In this paper we construct several examples of completely regular submetrizable quasitopological groups with slightly different combinations of properties, in particular, a countable quasitopological group $G$ with countable $\pi$-weight, countable tightness, countable $\delta$-character, but not first-countable, and a countable quasitopological group $P$ with countable $\pi$-weight, countable tightness, but of uncountable $\delta$-character.

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