Assume H2.
Apply H2 to the current goal.
Assume H2a: beta = alpha.
Apply PNoLtE alpha beta p q H1 to the current goal.
Apply Hpq1 to the current goal.
Let delta be given.
Assume Hpq2.
Apply Hpq2 to the current goal.
Apply binintersectE alpha beta delta Hd to the current goal.
Assume Hd1 Hd2.
Assume Hpq3.
Apply Hpq3 to the current goal.
Assume Hpq3.
Apply Hpq3 to the current goal.
Assume Hpq4: ¬ p delta.
Assume Hpq5: q delta.
Apply Hpq4 to the current goal.
An exact proof term for the current goal is iffEL (q delta) (p delta) (H2b delta Hd2) Hpq5.
Assume Hpq3: q alpha.
Apply In_irref alpha to the current goal.
rewrite the current goal using H2a (from right to left) at position 2.
An exact proof term for the current goal is Hpq1.
Assume Hpq3: ¬ p beta.
Apply In_irref alpha to the current goal.
rewrite the current goal using H2a (from right to left) at position 1.
An exact proof term for the current goal is Hpq1.