Is the で in ～が原因で～ the copula?


In constructs like ～が原因で起こった～ is the で the て form of だ?

For example in: 旦那や子どもへの嫉妬が原因で起こったママ友トラブル

I assume it is for the が to make sense, but I can't find any information on
this, so if anyone knows an answer would be greatly appreciated!




> 「旦那{だんな}や子{こ}どもへの嫉妬{しっと}が原因{げんいん} **で** 起{お}こったママ友{とも}トラブル」

That 「で」 is a particle and not a copula.

It can generally be said that 「で」 would be a particle unless it could
grammatically and contextually be replaced by 「であり」、「であって」、「であり、そして」, etc.

In the phrase in question, the 「で」 cannot be replaced by one of those phrases.

A good example of the copula 「で」 can be seen in this Q&A:

[How to parse
中国人で日本語が話せる方は、お電話ください。](https://japanese.stackexchange.com/questions/24917/how-
to-
parse-%e4%b8%ad%e5%9b%bd%e4%ba%ba%e3%81%a7%e6%97%a5%e6%9c%ac%e8%aa%9e%e3%81%8c%e8%a9%b1%e3%81%9b%e3%82%8b%e6%96%b9%e3%81%af-%e3%81%8a%e9%9b%bb%e8%a9%b1%e3%81%8f%e3%81%a0%e3%81%95%e3%81%84)

If you had a sentence such as:

> 「トラブルの原因はＡ **で** 、Ｂではない。」

then, that 「で」 in bold would certainly be a copula in the 連用形{れんようけい}
("continuative form").




> 「旦那{だんな}や子{こ}どもへの嫉妬{しっと}が原因{げんいん} **で** 起{お}こったママ友{とも}トラブル」

That 「で」 is a particle and not a copula.

It can generally be said that 「で」 would be a particle unless it could
grammatically and contextually be replaced by 「であり」、「であって」、「であり、そして」, etc.

In the phrase in question, the 「で」 cannot be replaced by one of those phrases.

A good example of the copula 「で」 can be seen in this Q&A:

[How to parse
中国人で日本語が話せる方は、お電話ください。](https://japanese.stackexchange.com/questions/24917/how-
to-
parse-%e4%b8%ad%e5%9b%bd%e4%ba%ba%e3%81%a7%e6%97%a5%e6%9c%ac%e8%aa%9e%e3%81%8c%e8%a9%b1%e3%81%9b%e3%82%8b%e6%96%b9%e3%81%af-%e3%81%8a%e9%9b%bb%e8%a9%b1%e3%81%8f%e3%81%a0%e3%81%95%e3%81%84)

If you had a sentence such as:

> 「トラブルの原因はＡ **で** 、Ｂではない。」

then, that 「で」 in bold would certainly be a copula in the 連用形{れんようけい}
("continuative form").

