(a) Vulnerability exerts influence solely in that some situations are forcing only when our side is vulnerable against not. Those situations include at least when the opponents bid at or above game and our side has shown strength or itself bid game nonpreemptively (but there is no agreement on other cases).
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North's pass is forcing only when vul vs non
(b) If we have been forced to game but have not bid game, competitive situations thereafter above the game level are forcing.
No idea about this.
© If we have bid game nonpreemptively, the default applies.
Which defalt?
(d) If we have invited game and the invitation has not been declined, competitive situations thereafter are forcing only as high as where the force would have expired noncompetitively.
I don't understand what's "as high as where the force would have expired noncompetitively"?
(e) A two-notrump opening does not create a force if the opponents bid.
pass is non-forcing
(f) If a two-club opening is overcalled, responder’s pass is forcing at every level.
pass is forcing
(g) No force is created after
(1) our penalty double or penalty pass of a takeout double when the partnership is not otherwise committed to further bidding;
(2) an opponent raises over our takeout double, simple overcall, or jump-overcall of a preemptive opening;
(3) an opponent’s preemptive bid over our one-over-one response;
(4) a strength-showing redouble by an already-limited hand.
(h) A strength-showing redouble by an unlimited hand creates a force to at least a level dictated by the logic of the auction
(g)123 is clear for me but not (g)4 or (h)