The Bg2xNc6 for Doubled c-Pawns Plan

The positon after 8...Be6(diagram) seems fairly innocuous.

8...Be6

Ex-World Champion Tigran Petrosian came up with the remarkable 9.Bxc6!? idea, giving up the strong bishop to play against the broken queenside pawns.

Ex-World Champion Petrosian,Tigran V

Photo Remizatorul Tigran-Petrosian

Here is the feature game.

Petrosian,Tigran V (2640) - Szabo,Laszlo (2565)
English 1.c4 Nf6 2.Nc3 c5 3.g3 d5 4.cxd5 Nxd5 5.Bg2 Nc7 [A34]
IBM Amsterdam (1), 1973

Position 1
Black is playing hard to exploit white's uncastled king and has given a piece for a pawn. White wants to neutralize black's threats as efficiently as possible. What do you recommend for white?

White to Play

19...Rd8

English Reversed Sicilian-Petrosian,T

The facing f-pawns plan(with Nh3)
The plan of f4 vs f5 facing f-pawn is an important defensive idea. Petrosian played 11.f4 to prevent the ...f4 idea and restrain Bc8, when black would have typical counterplay. The unique part of Petrosian's idea was to prepare and support f4 with Nh3.

11.f4

Here is the feature game.

Petrosian,Tigran V - Hort,Vlastimil 
English Reversed Sicilian[A25]
EU-chT (Men) Oberhausen (8.3), 29.06.1961

Position 1

Black is vulnerable but it is not easy to see exactly where. What do you recommend for white?

White to Play

17..de