somebody wrote a book about this several years ago. their idea was exploring different cuisines by their "holy trinity". french is onion, carrot, celery; spanish is garlic, tomato, pepper, italian is onion, garlic, tomato, chinese is green onion, garlic, ginger (all of these are from my increasingly shaky memory). it's an interesting conceit though i'm not sure how well it holds up to close examination. in Spanish, the mirepoix equivalent is sofrito (and in italian it's soffrito). you can omit celery in mirepoix if you want, but technically it's no longer a mirepoix ... which doesn't mean it's bad.