(R1) ¨ì (R5) §i¶D§ÚÌ R ¦b¥[ªk (+) ¹Bºâ¤U¬O¤@Ó abelian group. ©Ò¥H¦b group ¤¤ªº¤@¨Ç°ò¥»²z½×§Ú̳£¥i¥Hª½±µ®M¥Î. ¤ñ¤è»¡ 0 ¬O R ¤¤°ß¤@²Å¦X a + 0 = 0 + a = a ªº¤¸¯À (Proposition 1.2.1), ¥H¤Îµ¹©w a R ¥u¦s¦b°ß¤@ªº b R º¡¨¬ a + b = b + a = 0 (Proposition 1.2.2). ¨Ì²ßºD§Ú̱N¦¹ b °O°µ - a. ÁÙ¬On±j½Õ¤@¤U³o¸Ìªº 0 ¨Ã¤£¤@©w¬O¤j®a±`¬Ý¨ì¾ã¼Æ©Î¹ê¼Æ¤Wªº 0, ¦Ó - a ¤]¶Èªí¥Ü¬° a ªº¥[ªk¤§ inverse, ¨Ã¨S¦³¤@¯ë¥¿t¸¹ªº·N¸q.
§Ú̦C¥X¤@¨Ç group ªº©Ê½è¤è«K¥H«áª½±µ¤Þ¥Î.
(R6) ©M (R7) »¡©ú R ¤¤¼ªk ( . ) ³oÓ¹Bºâ¥»¨ªºn¨D. ª`·N³o¸Ì§Ų́å¼n¨D¼ªkªº identity ¥²¶·¦s¦b. ¤£¹LY¤@Ó ring ¹ï©ó¼ªk¨ä identity ¦s¦bªº¸Ü, §Y¨Ï¦b¼ªk¤§¤U R ¤£¤@©w·|¬O¤@Ó group ¦ý§Q¥Î©M Proposition 1.2.1 ¬Û¦Pªºµý©ú§ÚÌ¥iª¾¦¹ identity ¥²°ß¤@. ²ßºD¤W§ÚÌ·|¥Î 1 ¨Óªí¥Ü³o¤@Ó¼ªk¤Wªº identity (ª`·N: ³o¸Ìªº 1 ¨Ã¤£¤@©w¬O¤j®a±`¬Ý¨ì¾ã¼Æ©Î¹ê¼Æ¤Wªº 1). ¦pªG¤@Ó ring R ¨ä¼ªkªº identity ¦s¦b, ¨º»ò§ÚÌ´N·|¯S§O»¡©ú¦ÓºÙ R ¬O¤@Ó ring with 1.
¥t¥ (R6) ©M (R7) ¤]¨Sn¨D a . b = b . a. ¦pªG¤@Ó ring R ¤¤¹ï©Ò¦³ªº a, b R ¬Òº¡¨¬ a . b = b . a, §Ṳ́]·|¯S§O»¡©ú¦ÓºÙ R ¬O¤@Ó commutative ring (ª`·N: ¤£¬O abelian ring ³oÓ¦WºÙ). ¦b¤j¾Çªº°ò¦¥N¼Æ¤¤§ÚÌ·|¤ñ¸û±Mª`©ó commutative ring with 1 ³o¤@ºØ ring.
³Ì«á (R8) ´N¬Oµ²¦X ring ªº¥[ªk©M¼ªkªº¾ô¼Ù. ¤]¬O¦]¬°¥¦Åý ring ¾Ö¦³«Ü¦hº«Gªº©Ê½è, §Ú̦b¤U¤@¸`·|¬Ý¨ì¤@¨Ç§Q¥Î (R8) ©Ò±oªº ring ªº©Ê½è. ³o¸Ìnª`·Nªº¬O ring ¤£¤@©w¬O commutative ring, ©Ò¥H¹ï©ó¨âÃ䪺¤À°t²v§Ú̳£nn¨D.