Think grid.
Theory: with a spread of 0 (and tradecost of 0), if we trade at diverse levels (i.e. think two grids intermixed, or think numerous orders permitted), with diverse lot sizes, and hedging is allowed, then it's never possible to make sure a profit - however small - provided the amount of trades are limited/is finite (i.e. rules out mGrid/Williama).
True or false?