Pregroup tree rewrites: Possibility of merging nodes when > 1 children are present, but only one has the correct type

[dimkart]

Example ("the hunter shot the tall big bad wolf while a white aeroplane was passing on the blue sky"):

while_8 (s)
├ the hunter_1 (n)
├ shot_2 (n.r @ s)
│ └ the tall big bad wolf_7 (n)
└ was_12 (s)
  ├ a white aeroplane_11 (n)
  └ on_14 (n.r @ s)
    ├ passing_13 (n.r @ s)
    └ the blue sky_17 (n)

Note that "on" can be merged successfully with "passing" and the result is semantically correct. There is a possibility though that this doesn't work for everything, more tests are required.

Also relevant to DisCoCirc rewrite mechanism.