Gapping is a structure that in principle can only be found in coordination and not in subordination. When it appears, then, it confirms the presence of coordination in a language. It is a type of ellipsis [SYNTAX 2.5] in which a verb is removed in one, or more, of a series of conjuncts. In LSC, gapping occurs, thus confirming the presence of coordination. The verb can be missing only in the first conjunct, with an SOV-SO order, as in the example below.
ht-left ht-right ht-right
re re
marina coffee pay, jordi croissant pay.
‘Marina paid for a coffee and Jordi for a croissant.’
(© Giorgia Zorzi 2018. Reprinted with permission from Zorzi, 2018b: 278)
Gapping in LSC, though, can also appear in subordination, for instance in reason clauses [SYNTAX 3.5.5], as in the next example.
ht-right ht-right
re re re ht-right
marina fruit eat because jordi [cake eat][contra].
‘(*Marina ate fruits because Jordi some cake.)’
(© Giorgia Zorzi 2018. Reprinted with permission from Zorzi, 2018b: 282)
Gapping in LSC can appear in coordination and in subordination so this does not make it a very good test to establish the presence of coordination itself.