① <img class=jc-formula data-tex=若{ A }^{ 2 }=O,则A=O src=https://huaweicloudobs.ahjxjy.cn/3B66014D1B6692FC28DA836BA1245187.png style=vertical-align: middle;/>
② <img class=jc-formula data-tex=若{ A }^{ 2 }=A,则A=O或A=E src=https://huaweicloudobs.ahjxjy.cn/6E10525373636B3D0D16AA6AC9B5E162.png style=vertical-align: middle;/>
③ <img class=jc-formula data-tex=若{ A }X=AY,则X=Y src=https://huaweicloudobs.ahjxjy.cn/1786D86226E3FFF2862F9172E1D898F5.png style=vertical-align: middle;/>