Let x0 of type ι be given.
Apply set_ext with
d3786.. x0 x0,
x0 leaving 2 subgoals.
The subproof is completed by applying unknownprop_8f5bf12cfaed0ffd6b0b2703f40521e4f47dbe14ca71e17ebdcebdd96c630d67 with x0, x0.
Apply unknownprop_ca91282e0ce9e0658e00929623a7308f21757843a59143f77f3c318bcf850a5e with
x0,
x0,
x0 leaving 2 subgoals.
The subproof is completed by applying Subq_ref with x0.
The subproof is completed by applying Subq_ref with x0.