PIPE shows only one t-invariant in the net I attach:
1 1 0 0 0 0 1 0 0 0 0 0 0
what is true, but there exists additional invariants. The correct answer should be (this time in columns):
[1,00, 1,00, 1,00, 1,00 ]
[0,00, 0,00, 0,00, 1,00 ]
[1,00, 1,00, 1,00, 0,00 ]
[1,00, 1,00, 1,00, 1,00 ]
[0,00, 1,00, 1,00, 0,00 ]
[0,00, 1,00, 1,00, 0,00 ]
[1,00, 0,00, 0,00, 0,00 ]
[0,00, 2,00, 1,00, 0,00 ]
[0,00, 2,00, 1,00, 0,00 ]
[0,00, 1,00, 0,00, 0,00 ]
[0,00, 1,00, 0,00, 0,00 ]
[1,00, 0,00, 1,00, 0,00 ]
[1,00, 1,00, 1,00, 0,00 ]
(My answers has transitions sorted in order of their numbers, from top to down).
Note that this possibly will also happen for p-invariants if you consider net which has incidention matrix equal to the transposition of incidention matrix of the network I attached.
Net that causes problem