vertical trade

no response

What is vertical trade?

From what you have explained, I can see that you will lose in both cases, i.e. if you place two back bets at 1.6 and 2.5, presumably both £10, you will lose (1.6-2)*10 = -£4.

If you back at 2.5 then lay at 2.6 on the same player, or back 1.6, lay 1.7, you will get the reverse of hedging, i.e. all red instead of all green.

So what am I missing here?

example
tennis
player A   back 2.50 lay 2.60
player B    back 1.6   lay 1.7

place lay or back on two player to make a trading
instead lay then back (or back then lay) for same player.

not dutching

i place  lay 10 £ @1.7 on player B i must  place lay IN BELOW 2.32 on player A to make profit exact ?

with dutching i place two lays (tennis) for amount fixed

here i place  one lay  lay 10 £ @1.7 on player B then i must  place lay IN BELOW 2.42 (1/(1.7-1)+1) manualy on player A to make profit .