【判断题】
f为群到的同态映射,则f的同态核中只有一个元素,即的幺元。
【判断题】
R是A上的二元关系,R是自反的,当且仅当r(R)=R。
【判断题】
A、B、C为任意集合,已知A∪B=A∪C,必须有B=C。
【单选题】
<imgwidth="343"height="41"alt=""src="http://file.open.com.cn/ItemDB/3348/586b9990-3080-4ee6-94cb-b0783a744222/2009318101520825.JPG"/>
【单选题】
<imgsrc="http://121.251.253.213/doc/a@F7DFB53E01818944D852AA5ECC191CEC.png/download?time=636002423040255461&token=7E12063C1087B7CE79120A46C22C77A4&filename=png"data-preview_url_ueditor="doc/a@F7DFB53E01818944D852AA5ECC191CEC.png"data-url="doc/a@F7DFB53E01818944D852AA5ECC191CEC.png"/>
①
<imgsrc="http://121.251.253.213/doc/a@D21DE64C3DBA04E3EFF86EBC2F60CDEB.png/download?time=636002423445856173&token=C0943D40F3B2501A8F02FBEA0E2E2505&filename=png"data-preview_url_ueditor="doc/a@D21DE64C3DBA04E3EFF86EBC2F60CDEB.png"data-url="doc/a@D21DE64C3DBA04E3EFF86EBC2F60CDEB.png"/>
②
<imgsrc="http://121.251.253.213/doc/a@316FF33F9C0F2533BF47288DA9C8E085.png/download?time=636002423526664315&token=3BB1460E7F5D236EFB1518F30B5639C1&filename=png"data-preview_url_ueditor="doc/a@316FF33F9C0F2533BF47288DA9C8E085.png"data-url="doc/a@316FF33F9C0F2533BF47288DA9C8E085.png"/>
③
<imgsrc="http://121.251.253.213/doc/a@F6EC792366661495173DD40D102C98AD.png/download?time=636002423620108479&token=7F23A095B13B128BF438EF6731068BB5&filename=png"data-preview_url_ueditor="doc/a@F6EC792366661495173DD40D102C98AD.png"data-url="doc/a@F6EC792366661495173DD40D102C98AD.png"/>
④
<imgsrc="http://121.251.253.213/doc/a@61FCBA64D1107B85E22AF30B438DD9FD.png/download?time=636002423709652637&token=571DD66154D3E0DE24F32E569341FDCB&filename=png"data-preview_url_ueditor="doc/a@61FCBA64D1107B85E22AF30B438DD9FD.png"data-url="doc/a@61FCBA64D1107B85E22AF30B438DD9FD.png"/>
【单选题】
<imgsrc="http://121.251.253.213/doc/a@273879DE6423BE2E709315A0E4668C6B.png/download?time=636002413692251042&token=E3474BBE9C4022CD5EBACBF9CC7276F5&filename=png"data-preview_url_ueditor="doc/a@273879DE6423BE2E709315A0E4668C6B.png"data-url="doc/a@273879DE6423BE2E709315A0E4668C6B.png"/>
①
<imgsrc="http://121.251.253.213/doc/a@BBA8A5FF2BB7FFB000854ED17F7A66EE.png/download?time=636002413763231167&token=0AA905018DBBD2ECDB1D40FBAF64116A&filename=png"data-preview_url_ueditor="doc/a@BBA8A5FF2BB7FFB000854ED17F7A66EE.png"data-url="doc/a@BBA8A5FF2BB7FFB000854ED17F7A66EE.png"/>
②
<imgsrc="http://121.251.253.213/doc/a@32F816E1A35E0B2C69741D7EB262F482.png/download?time=636002413856675331&token=5BD0D363F1D679D4CC16C72971CEC7A5&filename=png"data-preview_url_ueditor="doc/a@32F816E1A35E0B2C69741D7EB262F482.png"data-url="doc/a@32F816E1A35E0B2C69741D7EB262F482.png"/>
③
<imgsrc="http://121.251.253.213/doc/a@64E1C45016A875270ADD44DD646BD9B8.png/download?time=636002413948871493&token=791C202D63C95CA99AB83A1F6F1E7DE9&filename=png"data-preview_url_ueditor="doc/a@64E1C45016A875270ADD44DD646BD9B8.png"data-url="doc/a@64E1C45016A875270ADD44DD646BD9B8.png"/>
④
<imgsrc="http://121.251.253.213/doc/a@4B8DD3C9F261F0664AE8BDE1F8CCAD89.png/download?time=636002414039039651&token=7ACAA576D52E5AE848DF68ACE7B6E1A7&filename=png"data-preview_url_ueditor="doc/a@4B8DD3C9F261F0664AE8BDE1F8CCAD89.png"data-url="doc/a@4B8DD3C9F261F0664AE8BDE1F8CCAD89.png"/>
【单选题】
<imgsrc="http://121.251.253.213/doc/a@9869E09EAF43605DEA686A47F51A268B.png/download?time=636002424844710630&token=3D81364A57C5910712E8421E058F4DFB&filename=png"data-preview_url_ueditor="doc/a@9869E09EAF43605DEA686A47F51A268B.png"data-url="doc/a@9869E09EAF43605DEA686A47F51A268B.png"/>
④
<imgsrc="http://121.251.253.213/doc/a@CF1BE005D8413A8F3A904618D0778415.png/download?time=636002424987918882&token=9C9A326147FAB1EC1580EE862DDAA93A&filename=png"data-preview_url_ueditor="doc/a@CF1BE005D8413A8F3A904618D0778415.png"data-url="doc/a@CF1BE005D8413A8F3A904618D0778415.png"/>
【单选题】
<imgsrc="http://121.251.253.213/doc/a@457B33C69788927B97EE709CCEE252B8.png/download?time=636002410647749695&token=781D4497E11B3670D9CCD8D1B59E3809&filename=png"data-preview_url_ueditor="doc/a@457B33C69788927B97EE709CCEE252B8.png"data-url="doc/a@457B33C69788927B97EE709CCEE252B8.png"/>
①
<imgsrc="http://121.251.253.213/doc/a@A54FF12616A47922F2C33DB081579836.png/download?time=636002410722629826&token=0511666BAE50F73C0EA8D99628F854FF&filename=png"data-preview_url_ueditor="doc/a@A54FF12616A47922F2C33DB081579836.png"data-url="doc/a@A54FF12616A47922F2C33DB081579836.png"/>
②
<imgsrc="http://121.251.253.213/doc/a@6ED0C0B76FD3C5879D169894755AE8BE.png/download?time=636002410840098032&token=8CC944AF7540098611C88DE9976000EB&filename=png"data-preview_url_ueditor="doc/a@6ED0C0B76FD3C5879D169894755AE8BE.png"data-url="doc/a@6ED0C0B76FD3C5879D169894755AE8BE.png"/>
③
<imgsrc="http://121.251.253.213/doc/a@899EDA616127ED81EA199B36DA1042CD.png/download?time=636002410929486189&token=E34E047DA33366C6B2270424EF901842&filename=png"data-preview_url_ueditor="doc/a@899EDA616127ED81EA199B36DA1042CD.png"data-url="doc/a@899EDA616127ED81EA199B36DA1042CD.png"/>
④
<imgsrc="http://121.251.253.213/doc/a@CBE8C80103D1EBD715F7A25059F97918.png/download?time=636002411045082392&token=9322A96C93EAFF8C8E0ABBC50DF4B253&filename=png"data-preview_url_ueditor="doc/a@CBE8C80103D1EBD715F7A25059F97918.png"data-url="doc/a@CBE8C80103D1EBD715F7A25059F97918.png"/>
【单选题】
<imgwidth="438"height="35"alt=""src="http://file.open.com.cn/ItemDB/3348/c90f4ed4-6261-46d8-9033-5b142c292889/20093181082534.JPG"/>