Where is arimasu?

where is: "conjugation for aru"?

I dont understand the question

There is an error in Provisional Form:

It should say "nakereba"

Peteroehr and turtleking, did you press the conjugation button? Also, from what I hear, the 漢字 in 有る is not commonly used that much anymore.

is ありえない a form of this verb?

Hey Madalena, tudo bem?

So, basically no. maybe you confused yourself because ありえない seems like a conjugation from ある.

But it is not. why not?

In general, there are some groups where you classify a japanese verb. these groups are Godan Verbs, Ichidan verbs or irregular verbs.

ある is a Godan Verb and あり得る (ありえる) is an Ichidan Verb.

Why is that so important? Because each group has a different method of attaching conjugational verb endings.

ありえる as an ichidan verb, as the rule says, you just have to cut the る and add ない to turn into negative form = ありえない

BUT, ある is an godan verb, not only this, it is an exception in godan verbs. the negative form of this particular verb (ある) is = ない

So, thats the difference I guess. I could explain in portuguese but english everyone does understand.

Additional informations or rectifications are welcome! 

Thanks Vinícius, that's a good explanation of why ありえない is not a conjugation of ある.

I'll just add that あ(あ)り(り)え(え)な(な)い(い) is actually a compound of あ(あ)る(る) in it's masu-form （あり） and the suffix 得(え)る(る) in it's negative form （得(え)な(な)い(い)）.

Put together it forms, あ(あ)り(り)・(・)得(え)な(な)い(い), meaning impossible; unlikely; improbable.

得(え)な(な)い(い) is a suffix that can be placed after the masu stem of a verb, to add a meaning of unable to, cannot, or a feeling of impossibility.

ie, 起(お)こ(こ)り(り)得(え)な(な)い(い)事(じ)故(こ) - an accident that cannot happen.