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well-known fact that Al-Jabr took some mathematical aspects from India and spread them across the Arabic countriesYour “Al-Jabr” (Short for Al-kitāb al-mukhtaṣar fī ḥisāb al-ğabr wa’l-muqābala, or The Compendious Book on Calculation by Completion and Balancing) was a book, written by Muḥammad ibn Mūsā al-Khwārizmī, who was Persian. Like other scholars writing in Arabic at the time, he read translations of Greek and Indian sources, while also doing significant original work.
The book of his which explained and advocated Indian numerals was a different book (not “Al-Jabr”). We have this in Latin translation so the original title is unknown, but Wikipedia speculatively lists Kitāb al-Jam‘ wat-Tafrīq bi-Ḥisāb al-Hind (The Book of Addition and Subtraction According to the Hindu Calculation).
[Edit: I just read the linked blog post which this discussion is ostensibly about, and noticed that the above was already described there. I assume you didn’t read it. You might want to start with that.]
If you want to play a game of “whose culture first invented everything”, we can trace a whole heck of a lot back to the Sumerians (and for what we can’t trace, who knows what still lies on some buried cuneiform tablet). But of course there were then crucial additional advancements made by Akkadians, Egyptians, Hellenes, Indians, Chinese, Arabs, Persians, Italians, French, English, Russians, Germans, Hungarians, Canadians, Japanese, .....
Mathematics is international and spreads easily. No culture can uniquely claim to have “invented” something as massive as “algebra”, even if we limit ourselves to topics taught in secondary school.