基礎知識
子圖的定義
![子圖](/img/9/e9b/wZwpmL1UDN3cTOxkjN2UzM1UTM1QDN5MjM5ADMwAjMwUzL5YzL0gzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/7/949/wZwpmL4YDNwETNyQTO2UzM1UTM1QDN5MjM5ADMwAjMwUzL0kzLxMzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/2/f7a/wZwpmLwEjN4MDMzQDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL0gzL0gzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/0/212/wZwpmL2UTM5UDNxYDM3UzM1UTM1QDN5MjM5ADMwAjMwUzL2AzL1UzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![子圖](/img/8/93a/wZwpmL1gjNwITOxIDM3UzM1UTM1QDN5MjM5ADMwAjMwUzLyAzL2EzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/0/74e/wZwpmL1ATOxETMzQDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL0gzLxQzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![子圖](/img/4/947/wZwpmLycDM1EDM2QzN2UzM1UTM1QDN5MjM5ADMwAjMwUzL0czL4UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
設 為兩個圖(同為無向圖或同為有向圖),若 且 ,則稱G'是G的 子圖,G是G‘的 母圖,記作 ,又若 且 ,則G'稱是G的 真子圖,若 ,則稱G'是G的 生成子圖。
![子圖](/img/f/4ef/wZwpmLyQDN5QTO0QzM3UzM1UTM1QDN5MjM5ADMwAjMwUzL0MzLyUzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/8/93a/wZwpmL1gjNwITOxIDM3UzM1UTM1QDN5MjM5ADMwAjMwUzLyAzL2EzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/d/a7a/wZwpmLyQDN0MDM1kDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL5gzLxYzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/e/79f/wZwpmLwQDM1ETM5ATMzEzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL1EzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/e/79f/wZwpmLwQDM1ETM5ATMzEzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL1EzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/5/a10/wZwpmLyADN0kjM2MzNwIDN0UTMyITNykTO0EDMwAjMwUzLzczL0IzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![子圖](/img/e/79f/wZwpmLwQDM1ETM5ATMzEzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL1EzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/7/189/wZwpmL4YDM0UjM1QDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL0gzL0gzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/0/ab3/wZwpmLyADN3cDOzQDN3UzM1UTM1QDN5MjM5ADMwAjMwUzL0QzLxIzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![子圖](/img/0/831/wZwpmLxEDOwYjN4cTO2UzM1UTM1QDN5MjM5ADMwAjMwUzL3kzL4gzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/5/a10/wZwpmLyADN0kjM2MzNwIDN0UTMyITNykTO0EDMwAjMwUzLzczL0IzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![子圖](/img/5/a10/wZwpmLyADN0kjM2MzNwIDN0UTMyITNykTO0EDMwAjMwUzLzczL0IzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![子圖](/img/e/79f/wZwpmLwQDM1ETM5ATMzEzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL1EzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/5/a10/wZwpmLyADN0kjM2MzNwIDN0UTMyITNykTO0EDMwAjMwUzLzczL0IzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![子圖](/img/b/7d2/wZwpmL3MjN3EDNxEDN3UzM1UTM1QDN5MjM5ADMwAjMwUzLxQzL0UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
設 為一圖, 且 ,稱以 為頂點集,以G中兩個端點都在 中的邊組成邊集 的圖為G的 導出子圖,記作 ,又設 且 ,稱以 為邊集,以 中邊關聯的頂點為頂點集 的圖為G的 導出的子圖,記作。
![子圖](/img/b/9fa/wZwpmLyIzM0YTO5MDM3UzM1UTM1QDN5MjM5ADMwAjMwUzLzAzLzYzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/e/79f/wZwpmLwQDM1ETM5ATMzEzM1UTM1QDN5MjM5ADMwAjMwUzLwEzL1EzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/7/189/wZwpmL4YDM0UjM1QDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL0gzL0gzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/0/05f/wZwpmLxcTNykTNwYDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL2gzL0YzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/5/a10/wZwpmLyADN0kjM2MzNwIDN0UTMyITNykTO0EDMwAjMwUzLzczL0IzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![子圖](/img/b/7d2/wZwpmL3MjN3EDNxEDN3UzM1UTM1QDN5MjM5ADMwAjMwUzLxQzL0UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
在圖1中,設G如圖1(a)所示,取 ,則 的導出子圖 如圖1(b)所示,取 ,則 的導出子圖 如圖1(c)所示。
![圖1(a)](/img/1/3d6/wZwpmL1gTM2YzM4UjN2UzM1UTM1QDN5MjM5ADMwAjMwUzL1YzL4MzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![圖1(b)](/img/3/1b9/wZwpmLygTOykjMxYDN3UzM1UTM1QDN5MjM5ADMwAjMwUzL2QzL2AzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![圖1(c)](/img/d/3a3/wZwpmL4YzN5IzN1kzM3UzM1UTM1QDN5MjM5ADMwAjMwUzL5MzL2EzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
補圖
![子圖](/img/f/4ef/wZwpmLyQDN5QTO0QzM3UzM1UTM1QDN5MjM5ADMwAjMwUzL0MzLyUzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/8/2fd/wZwpmLxIzM0cDO4MTNxMzM1UTM1QDN5MjM5ADMwAjMwUzLzUzL1YzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/2/29d/wZwpmL2gzNzQDOxczMxMzM1UTM1QDN5MjM5ADMwAjMwUzL3MzLwYzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
設 為n階無向簡單圖,以V為頂點集,以所有使G成為完全圖的 的添加邊組成的集合為邊集的圖,稱為G的 補圖,記作。
![子圖](/img/e/ec6/wZwpmLyYDM1IDN3MTO2UzM1UTM1QDN5MjM5ADMwAjMwUzLzkzL4YzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
若圖 ,則稱G是自補圖。
圖2中,(b)和(c)互為補圖,(a)是自補圖。
![圖2(a)](/img/6/a71/wZwpmLxATO4ATNyYzM3UzM1UTM1QDN5MjM5ADMwAjMwUzL2MzL2gzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![圖2(b)](/img/e/7a1/wZwpmL3UTO5ATOwQDN3UzM1UTM1QDN5MjM5ADMwAjMwUzL0QzL2IzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![圖2(c)](/img/4/541/wZwpmLzYTO5MTO2gzM3UzM1UTM1QDN5MjM5ADMwAjMwUzL4MzLyczLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
相關定理
![子圖](/img/7/398/wZwpmL2ATN0ETMzMTO2UzM1UTM1QDN5MjM5ADMwAjMwUzLzkzL1gzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/8/193/wZwpmLzIDNycTM0MjN2UzM1UTM1QDN5MjM5ADMwAjMwUzLzYzL0YzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![子圖](/img/6/bf6/wZwpmL3YDM2QTN3cTO2UzM1UTM1QDN5MjM5ADMwAjMwUzL3kzLzYzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
若n階圖G是自補圖,則或,k為非負整數,且圖G有條邊。
![子圖](/img/2/29d/wZwpmL2gzNzQDOxczMxMzM1UTM1QDN5MjM5ADMwAjMwUzL3MzLwYzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/8/2fd/wZwpmLxIzM0cDO4MTNxMzM1UTM1QDN5MjM5ADMwAjMwUzLzUzL1YzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/9/9f1/wZwpmLxgzNyUzNyMjM0EDN0UTMyITNykTO0EDMwAjMwUzLzIzLwgzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/2/29d/wZwpmL2gzNzQDOxczMxMzM1UTM1QDN5MjM5ADMwAjMwUzL3MzLwYzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/2/29d/wZwpmL2gzNzQDOxczMxMzM1UTM1QDN5MjM5ADMwAjMwUzL3MzLwYzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/6/bf6/wZwpmL3YDM2QTN3cTO2UzM1UTM1QDN5MjM5ADMwAjMwUzL3kzLzYzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/f/97c/wZwpmL4QzM5QzN0cDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL3gzLzczLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/7/398/wZwpmL2ATN0ETMzMTO2UzM1UTM1QDN5MjM5ADMwAjMwUzLzkzL1gzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/8/193/wZwpmLzIDNycTM0MjN2UzM1UTM1QDN5MjM5ADMwAjMwUzLzYzL0YzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
證明:因為n階圖G是自補圖,所以G與同構。於是完全圖的條邊將各有一半為G與的邊,即G與均有條邊。而圖G的邊數是非負整數,故4一定能整除,而連續的兩個整數n-1與n總是一個為奇數,一個為偶數,故或(k為非負整數)。證畢。
![圖3(a)](/img/f/e7e/wZwpmLxYDNxgTM4gjN2UzM1UTM1QDN5MjM5ADMwAjMwUzL4YzLzYzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![圖3(b)](/img/b/0ef/wZwpmLxgDN3QjM3kjN2UzM1UTM1QDN5MjM5ADMwAjMwUzL5YzLwgzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
圖的操作
![子圖](/img/f/4ef/wZwpmLyQDN5QTO0QzM3UzM1UTM1QDN5MjM5ADMwAjMwUzL0MzLyUzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
設為無向圖。
![子圖](/img/b/3ca/wZwpmLyETMyQTN1UzN2UzM1UTM1QDN5MjM5ADMwAjMwUzL1czLzMzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/8/cd4/wZwpmL2ATN2MDOyMTO2UzM1UTM1QDN5MjM5ADMwAjMwUzLzkzL1YzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/0/74e/wZwpmL1ATOxETMzQDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL0gzLxQzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![子圖](/img/0/dad/wZwpmL0czM1ITMzQDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL0gzL2MzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
(1)設,用表示從G中去掉邊e,稱為 刪除邊e。又設,用表示從G中刪除E'中的所有邊,稱為刪除E'。
![子圖](/img/c/88b/wZwpmL4UDM2UzNwczNwMzM1UTM1QDN5MjM5ADMwAjMwUzL3czL3QzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![子圖](/img/9/584/wZwpmLyYDN4IzMxQDM3UzM1UTM1QDN5MjM5ADMwAjMwUzL0AzLzczLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![子圖](/img/8/93a/wZwpmL1gjNwITOxIDM3UzM1UTM1QDN5MjM5ADMwAjMwUzLyAzL2EzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/f/fe2/wZwpmLwAzM4UTO5cDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL3gzL0YzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/7/687/wZwpmL3MDM0YTNwADN3UzM1UTM1QDN5MjM5ADMwAjMwUzLwQzL2IzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
(2)設,用表示從G中去掉v及所關聯的一切邊,稱為 刪除頂點v,又設,用表示從G中刪除中的所有邊,稱為刪除V'。
![子圖](/img/f/920/wZwpmL2UTN5QjNyYDM3UzM1UTM1QDN5MjM5ADMwAjMwUzL2AzL4EzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/e/3da/wZwpmL4cDOyITM5YTO2UzM1UTM1QDN5MjM5ADMwAjMwUzL2kzLzEzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
(3)設邊,用表示從G中刪除e後,將e的兩個端點u,v用一個新的頂點w(或用u或用v充當w)代替,使w關聯e以外u,v關聯的所有邊,稱為邊e的 收縮。
![子圖](/img/4/521/wZwpmL3cTOyMjN3EDN3UzM1UTM1QDN5MjM5ADMwAjMwUzLxQzL3EzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![子圖](/img/3/9c6/wZwpmL3AzMxUDO5kzM3UzM1UTM1QDN5MjM5ADMwAjMwUzL5MzLzEzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/c/ef9/wZwpmLzgDN2AzN5EDM3UzM1UTM1QDN5MjM5ADMwAjMwUzLxAzLwUzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/d/a87/wZwpmLwQTMzgjNzUjMxMzM1UTM1QDN5MjM5ADMwAjMwUzL1IzL2QzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
(4)設(u,v可能相鄰,也可能不相鄰),用(或)表示在u,v之間加一條邊,稱為 加新邊。
在收縮邊和加新邊過程中可能產生環和平行邊。
![子圖](/img/0/d3a/wZwpmL0MTNzADN4UzN2UzM1UTM1QDN5MjM5ADMwAjMwUzL1czL2gzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![子圖](/img/5/8a7/wZwpmLwAjM0kjMyUTO2UzM1UTM1QDN5MjM5ADMwAjMwUzL1kzL4QzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![子圖](/img/5/c8b/wZwpmLycjNzUzNwcjN2UzM1UTM1QDN5MjM5ADMwAjMwUzL3YzLzYzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/5/917/wZwpmL0ADMyITNyQDM3UzM1UTM1QDN5MjM5ADMwAjMwUzL0AzLzQzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![子圖](/img/5/e42/wZwpmLxYzM5IjM1MDO2UzM1UTM1QDN5MjM5ADMwAjMwUzLzgzLyEzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![子圖](/img/b/df2/wZwpmLxQzM0EDM2QTO2UzM1UTM1QDN5MjM5ADMwAjMwUzL0kzL2gzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
在圖4中,設(a)圖為G,則(b)圖為,(c)圖為,(d)圖為,(e)圖為,而圖為。
![圖4(a)](/img/7/2ad/wZwpmL4UjM4kTO2EDM3UzM1UTM1QDN5MjM5ADMwAjMwUzLxAzL1MzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![圖4(b)](/img/3/4a3/wZwpmLzMTO2czN3IzN2UzM1UTM1QDN5MjM5ADMwAjMwUzLyczLxgzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![圖4(c)](/img/4/c61/wZwpmLxYTN3kTMzEDM3UzM1UTM1QDN5MjM5ADMwAjMwUzLxAzL3EzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![圖4(d)](/img/c/1e0/wZwpmLyIzM3kzM1QzN2UzM1UTM1QDN5MjM5ADMwAjMwUzL0czLwUzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![圖4(e)](/img/1/6f3/wZwpmLzATO3MzMykzM3UzM1UTM1QDN5MjM5ADMwAjMwUzL5MzLyYzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![圖4(f)](/img/a/c92/wZwpmL0ADOyYDN5kDO2UzM1UTM1QDN5MjM5ADMwAjMwUzL5gzLwUzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)