Corrected the indexing of the tensor product CxI

]]>That looks much better. It must have been that italics problem that Andrew fixed.

]]>Oh, sorry. I guess Andrew just fixed this. Or something. It looks good now.

]]>It’s the same for me, yes. Many of these commuting diagrams on the $n$Lab don’t look well on my browser (latest Firefox on Windows). All the arrows are tilted.

]]>With reference to the italics in mathematics discussion, on my Browser (Firefox on a Mac) the ordinary downarrows are slanting left in that diagram. Is this the case on all browsers?

]]>expanded *chain homotopy*: added the usual non-commuting diagram, a discussion of chain homotopy equivalence and slightly expanded the description in terms of left homotopy