CZ-0001

[MURATA Makoto (FAMILY Given)]

(Wearing my RNG geek hat)

Czech proposed to replace 

sml_CT_CalcCell =
  attribute r { sml_ST_CellRef }?,
  attribute ref { sml_ST_CellRef }?,

by 

sml_CT_CalcCell = 
(attribute r { sml_ST_CellRef } | 
attribute ref { sml_ST_CellRef }), 

since either @r or @ref is required but not both.

I believe that this makes perfect sense.  Note that the OOXML RELAX NG
schemas are sometimes more strict than the OOXML XSD schemas already 
(e.g., root elements).

Cheers,
Makoto