How white win this position and why?

White to play 

Is there any  theory in this position? 

you are right 

but why？

@1
"Is there any  theory in this position?"
++ It is the theory of corresponding squares as you find in any book on pawn endgames.

Well, for e3 to be a legal move, there has to be a white pawn on e2. After that, winning is super easy.

I know there is something called "theory of corresponding squares", but I just don't know how to use it in the pratical game.

According to "theory of corresponding squares", it seems that white king moves to e3, black king  cannot find a corresponding squares to answer that move.But if white king move to anywhere else ,the game will be a draw.

 could you explain it in detail to me? thank you in advance!

b4 pawn is the key player.

Hi,  in this position, if white  moves  his king to e3 ,he will win the game. 

It is the answer to this puzzle , but  I don't know how to find this Ke3 move.(the theory behind this move ,it seems related to "theory of corresponding squares" or something like that )

Could you help me?

I was just joking. The guy said "e3" instead of "Ke3", that was the base of the joke. But whatever.

The position is not complicated, you just need to calculate stuff. Black's plan to easily draw is simple: 1. - Kf6, then 2. - h5, after that white can't dream of winning. The only way to counter this plan is to defend the f5 pawn after black plays 1. - Kf6. And the only way to do it is to play 1. Ke3 Kf6 2. Ke4. Nothing else works, just look at it yourself.

@10
Here is an explanation
https://en.wikipedia.org/wiki/Corresponding_squares 

White wants go get the king to e5.  An intermediate goal is to get the king to play Ke4 when Black cannot respond with Kf6 (playing Ke4 is good if Black is already on f6).

Remember that if Black ever plays h5 the White can play gxh5 and as long as Black cannot respond with an immediate Kxf5 then the two disconnected pawns will win against the Black king (White is free to eventually take the g5 pawn and assist the White pawns that are immune from capture (capturing one will let the other queen).

Example of the strength of the two pawns if Black sacrifices to split them up)

1 Ke3 h5

2 gxh5 Kf6 (to try to capture the f pawn and then come back for the h pawn)

3 h6 Kf7 (3 ... Kxf5 4 h7 and 5 h8=Q)

4 Kf3 (going for the g pawn) Kf6 (4 ... Kg8 5 f6 and the next two pawn moves by White are to move and then queen the pawn that is not on the file Black moves its king to)

5 Kg4 Kf7 (same reason as on move 3)

6 Kxg5 and the two pawns are escorted (just make sure that an eventual f7 does not stalemate a Black king sitting on h8 and an eventual f8=Q does not stalemate a Black king sitting on h7)

Thank you for you all

:shock

There is no opposition anywhere in this puzzle.