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ve ©Hj ?_] 1.1
>i ©¬ ? ¢À [1 - 4] s??i(binary operation) ¨ö©¬ O? < u n) u ¡Æs &_?. ?
a * a a a b b c c d a e e ? ? |¨ö S = {a, b, c, d, e} 0\" ©ø 1.4 H E 9+ A?f ©£ b b c a e b c c a b b a d b e b e d e d c a d c
1. b ? d, c ? c, [(a ? c) ? e] ? a \ >i
. | ? ©¬ ¡¤ l. b ? d = e, c ? c = b, [(a ? c) ? e] ? a = (c ? e) ? a = a ? a = a. ? < | ? ©¬¢¬ ©¬? i? ? E: +OE 2. (a ? b) ? c u a ? (b ? c) \ >i
r?. s >i\ l?
# ? ¨öZg (associative law)` e7
?t #?t\ ¢¥¨ö A e?? | ?¢´ H ©¬a Q( u+ ¨¬ ? | ?E H ¡¤ l. (a ? b) ? c = b ? c = a, a ? (b ? c) = a ? a = a. s ze t?? ¢¥ ©¬ | u ¢¥? H? E + ¨¬ O ¨ö A \. ? 3. (b ? d) ? c u b ? (d ? c) \ >i
r?. s >i\ l?
# ? ¨öZg < | ? ©¬¢¬ ©¬? i? ? E: +OE | ?¢´ H ©¬a Q( u+ ¨¬ ? ` e7
?t #?t\ ¢¥¨ö A e?? | ?E H ¡¤ l. (b ? d) ? c = e ? c = a, b ? (d ? c) = b ? b = c. ? ? ¨öZg` e7
H E:| ?¢´ +OE ©¬a t ¡¤?? ¢¥¨ö A e. ? u| u+ ¨¬ ? ¡×H ?E 4. ? ? ?¡§Zg(commutat