Premise: Around 130 flights were cancelled during a strike held on 19 January, and others were cancelled in the days that followed. When the flight assistants announced a further 24-hour for 23 January, the Italian Guarantee Authority (Commissione di Garanzia) which regulates strikes in essential public services (under the terms of laws no. 194/1990 and no. 83/2000) (IT0004266F) accused the unions of breaching the legal provision that 10 days must elapse between one strike and the next.
Hypothesis: 7 days must elapse between one strike and the next.