Stars and men revolve in a cycle . . .

In a book-discussion group in which I participate, we are reading some of the short fiction of Jorge Luis Borges (1899-1986) and that reading has provoked me to dive again into my copy of his Selected Poems (Ed. Alexander Coleman, Penguin, 1999).  Here is one of Borges' poems that uses terminology from mathematics:

The Cyclical Night     by Jorge Luis Borges
                                             tr. Alistair Reid (1926-2014)
          to Sylvina Bullrich

 They knew it, the fervent pupils of Pythagoras:
 That stars and men revolve in a cycle,
 That fateful atoms will bring back the vital
 Gold Aphrodite, Thebans, and agoras. 

Open and Closed -- Tomas Transtromer

A background in mathematics gives my enchantment with words a special twist. Each time I see familiar math terms in a poem I layer their mathematical meanings amid their mainstream ones. Two such terms are "open" and "closed." (I'll supply brief mathematical explanation at the end of this post but, first, here is "Open and Closed Spaces" -- a poem by the winner of the 2011 Nobel prize  for Literature, Swedish poet Tomas Transtromer. )