Ryan was the first person to express "there" with symbols. In an algebra book 1659, he used two symbols to mean "so": ∴ "and √", among which ∴ "was used more. 1668 The English version of this book is also written by.

/kloc-at the beginning of the 0/8th century, no one used "⊙" to mean "because". It was not until 1805 that "⊙" was used to express "because" for the first time in the Handbook of Popular Mathematics published in Britain, but it was not as widely used as "so".