it makes a big difference to a thinking reg. My utg range is tighter than my H-J range which is tighter than my co range. If they're 3b the same hands regardless of where i opened then I would no longer call them a "decent reg" (the question assumes they are).
It isn't "level 3" just Maths... also I said we are decent regs.. not overly loose.. just not nits.
Oh, and I should clarify that this is online 100bb poker. I should have said that in the original post, but can't edit now
Nope. Totally and wholeheartedly disagree.
I might assume that despite your "math" protestation you don't have a degree in Economics or Finance. If you have one in Math or Statistics, you should ask for a refund.
What you're describing is a fallacy of both Game Theory and everyday activity. You're confusing correlation with causation. You think that "because he is a thinking reg" that your starting position CAUSES his 3 bet on the button. It doesn't. Ever. It is merely a factor, that is, correlated to the fact that you opened from ANY of the 3 mentioned positions.
I gave you the benefit of the doubt and an out to find you doing Level 3 Strategy here, which is well known and easily known by both of you. That is to say, well, he 3 bet me because he thinks I think X. But I know that he could 3 bet me because he thinks I think X and so his range is weaker than normally expected and so I can call or 4 bet knowing this. BUT, he knows that YOU KNOW all this and could be thinking it. SO, is he 3 betting you trying to build a pot with you misreading the situation? Or is he 3 betting you trying to get you to give up on the hand because of the he knows that I know that he knows that I know situation.
I will tell you two things definitively. Regardless of his cards, and regardless of the range he puts you on, he is NOT 3 betting you looking for a fold. So now you have to figure out, does he want me to call because he believes he has a strong advantage or does he want me to call to build a pot where he can REPRESENT a strong advantage and take it down on the turn or river once a decent pot has been built? Point #2 is that your position DOES NOT MATTER AT ALL. I promise I'm not trying to be mean, but I tell it like it is. Game Theory dating back to John Nash proves that when he acts his only concern about position is that he has it and you don't. (This is assuming you are head's up already. If you're not, you totally need to work on your layout skills because you made it seem that way)
So now go back to my original response to see how I would approach the situation. In case it isn't totally obvious, I would approach it exactly the same from every position.
The only caveat that would have been available here (which you did not use to your advantage) is IF you had limped from UTG, it folded around to him on the button, he makes it ANYWHERE in the range you find yourself in now 3-9bb, the blinds fold and it is back to you. Maybe a 9bb open from the button should be flatted for 100 different reasons of how to win from there. But MOST of that range gives you the option of re-popping HUGE and winning one of two ways: either TID right there, or TID on later streets due to expected range. If you guys haven't seen enough of it on tv yet, you can expect a ton of THIS EXACT PLAY of limp/raising UTG as a declaration of strength. Obviously, to balance your range, you need to do this with premium hands as well as others you might not want to. But that's how to make it profitable.