11 lines
291 B
Text
11 lines
291 B
Text
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open eq tactic
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open eq (rec_on)
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definition concat_whisker2 {A} {x y z : A} (p p' : x = y) (q q' : y = z) (a : p = p') (b : q = q') :
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(whiskerR a q) ⬝ (whiskerL p' b) = (whiskerL p b) ⬝ (whiskerR a q') :=
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begin
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apply (rec_on b),
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apply (rec_on a),
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apply ((concat_1p _)⁻¹),
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end
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