@inproceedings { Gutman20180919, author = "Gutman A.E.", title = "Archimedean and directionally closed cones", booktitle = "Geometry Days in Novosibirsk -- 2018. International conference (Novosibirsk, September 19--22, 2018): Proceedings", address = "Novosibirsk", publisher = "Institute of Mathematics", year = "2018", isbn = "978-5-86134-220-9", pages = "15", annote = "A criterion is provided for a wedge to be Archimedean, which is based on the notion of closed set along a direction." }