Let x0 of type ι be given.

Let x1 of type ι be given.

Assume H0: atleastp x0 x1.

Assume H1: atleastp x1 x0.

Apply H0 with equip x0 x1.

Let x2 of type ι → ι be given.

Assume H2: inj x0 x1 x2.

Apply H1 with equip x0 x1.

Let x3 of type ι → ι be given.

Assume H3: inj x1 x0 x3.

Apply SchroederBernstein with x0, x1, x2, x3 leaving 2 subgoals.

The subproof is completed by applying H2.

The subproof is completed by applying H3.

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Proofgold Proof