Abstract:The problem of Y. Tanaka [10] of characterizing the topologies whose products with each first-countable space are sequential, is solved. The spaces that answer the problem are called strongly sequential spaces in analogy to strongly Fr\'echet spaces.
Keywords: sequential, Fr\'echet, strongly Fr\'echet topology, product convergence, Antoine convergence, continuous convergence
AMS Subject Classification: 54B10, 54D55, 54A20, 54B30