Articles are often omitted in mathematical writing and discourse, for the sake of brevity. The rules, however, are quite complex, and are usually learned by practise and example. See Writing Mathematical Papers in English by Dr. Jerzy Trzeciak for more information.
In your example, the articles can be omitted without any loss of meaning, although I make this statement from memory. I stopped doing maths decades ago.
Jerzy Trzeciak, Writing Mathematical Papers in English, European Mathematical Society, 1995
Trzeciak's text mentions article omission...
..."[i]n front of nouns referring to properties if you mention no