equal
deleted
inserted
replaced
279 |
279 |
280 |
280 |
281 subsection \<open>Product\<close> |
281 subsection \<open>Product\<close> |
282 |
282 |
283 definition cprod (infixr "*c" 80) where |
283 definition cprod (infixr "*c" 80) where |
284 "r1 *c r2 = |Field r1 <*> Field r2|" |
284 "r1 *c r2 = |Field r1 \<times> Field r2|" |
285 |
285 |
286 lemma card_order_cprod: |
286 lemma card_order_cprod: |
287 assumes "card_order r1" "card_order r2" |
287 assumes "card_order r1" "card_order r2" |
288 shows "card_order (r1 *c r2)" |
288 shows "card_order (r1 *c r2)" |
289 proof - |
289 proof - |