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Axiom TR caps.svg LaTeX source documentclass amsart usepackage amsmath amssymb nopageno usepackageall xy begin document begin align underset text large lower cap xymatrix em X' ardddd arddrri arllll aruurrv arddllj Z' arrrrr aruullu aruuuu circ underset text large upper cap xymatrix em X' ardddd arllll arddll Y' aruull