Also added cross-pointer with T-duality 2-group
]]>Thanks. I have added the publication data to the item, and copied it over also to 2-group. Also I adjusted the line “On categorical extensions of a torus by the circle” to “On 2-group extensions of tori by the circle 2-group”
]]>Added another reference
Fixed the link for Subtle symmetries and the refined Monster.
]]>