После изучения аналогичных примеров у меня получилось следующее.
Шаг 1.
![$% MathType!MTEF!2!1!+-
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% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGimaaaa!3979!
\[
\varphi = 0
\]
$ $% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGimaaaa!3979!
\[
\varphi = 0
\]
$](https://dxdy-01.korotkov.co.uk/f/c/2/a/c2a2ddb5dbfe798f66b8ac0240ff21ff82.png)
Шаг 2. Рассмотрим путь S-A-B-T. Можем увеличить поток на величину 1,1.
Тогда
![$% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGimaiabgUcaRiaaigdacaGGSaGaaGymaiabg2da9iaaigda
% caGGSaGaaGymaaaa!3FAD!
\[
\varphi = 0 + 1,1 = 1,1
\]
$ $% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGimaiabgUcaRiaaigdacaGGSaGaaGymaiabg2da9iaaigda
% caGGSaGaaGymaaaa!3FAD!
\[
\varphi = 0 + 1,1 = 1,1
\]
$](https://dxdy-01.korotkov.co.uk/f/4/e/8/4e81d86f90465bbed5cf8a06f158916882.png)
Дуга B-T становится насыщенной

Шаг 3. Рассмотрим путь S-D-T. Можем увеличить поток на величину 3,2.
Тогда поток
![$% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGymaiaacYcacaaIXaGaey4kaSIaaG4maiaacYcacaaIYaGa
% eyypa0JaaGinaiaacYcacaaIZaaaaa!4121!
\[
\varphi = 1,1 + 3,2 = 4,3
\]
$ $% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGymaiaacYcacaaIXaGaey4kaSIaaG4maiaacYcacaaIYaGa
% eyypa0JaaGinaiaacYcacaaIZaaaaa!4121!
\[
\varphi = 1,1 + 3,2 = 4,3
\]
$](https://dxdy-03.korotkov.co.uk/f/a/5/c/a5c43347745691eda1682b4fd7998b4a82.png)
Дуга S-D насыщена

Шаг 4. Рассмотрим путь S-C-T. Можем увеличить поток на величину 2,2.
Тогда поток
![$% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGinaiaacYcacaaIZaGaey4kaSIaaGOmaiaacYcacaaIYaGa
% eyypa0JaaGOnaiaacYcacaaI1aaaaa!4129!
\[
\varphi = 4,3 + 2,2 = 6,5
\]
$ $% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGinaiaacYcacaaIZaGaey4kaSIaaGOmaiaacYcacaaIYaGa
% eyypa0JaaGOnaiaacYcacaaI1aaaaa!4129!
\[
\varphi = 4,3 + 2,2 = 6,5
\]
$](https://dxdy-04.korotkov.co.uk/f/b/0/1/b01487ef9f984d7e04f69f649de195f282.png)
Дуга S-C насыщена

Шаг 5. Рассмотрим путь S-A-B-D-T. Можем увеличить поток на величину
![$% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciyBaiaacM
% gacaGGUbWaaeWaaeaacaaI1aGaaiilaiaaikdacqGHsislcaaIXaGa
% aiilaiaaigdacaGG7aGaaGynaiaacYcacaaIYaGaeyOeI0IaaGymai
% aacYcacaaIXaGaai4oaiaaikdacaGGSaGaaGymaiaacUdacaaI1aGa
% aiilaiaaiodacqGHsislcaaIZaGaaiilaiaaikdaaiaawIcacaGLPa
% aacqGH9aqpcaaIYaGaaiilaiaaigdaaaa!5197!
\[
\min \left( {5,2 - 1,1;5,2 - 1,1;2,1;5,3 - 3,2} \right) = 2,1
\]
$ $% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciyBaiaacM
% gacaGGUbWaaeWaaeaacaaI1aGaaiilaiaaikdacqGHsislcaaIXaGa
% aiilaiaaigdacaGG7aGaaGynaiaacYcacaaIYaGaeyOeI0IaaGymai
% aacYcacaaIXaGaai4oaiaaikdacaGGSaGaaGymaiaacUdacaaI1aGa
% aiilaiaaiodacqGHsislcaaIZaGaaiilaiaaikdaaiaawIcacaGLPa
% aacqGH9aqpcaaIYaGaaiilaiaaigdaaaa!5197!
\[
\min \left( {5,2 - 1,1;5,2 - 1,1;2,1;5,3 - 3,2} \right) = 2,1
\]
$](https://dxdy-03.korotkov.co.uk/f/6/8/6/6867cbfd7827223b06649c705aa1ad6482.png)
Тогда поток
![$% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGOnaiaacYcacaaI1aGaey4kaSIaaGOmaiaacYcacaaIXaGa
% eyypa0JaaGioaiaacYcacaaI2aaaaa!412F!
\[
\varphi = 6,5 + 2,1 = 8,6
\]
$ $% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqy1dOMaey
% ypa0JaaGOnaiaacYcacaaI1aGaey4kaSIaaGOmaiaacYcacaaIXaGa
% eyypa0JaaGioaiaacYcacaaI2aaaaa!412F!
\[
\varphi = 6,5 + 2,1 = 8,6
\]
$](https://dxdy-04.korotkov.co.uk/f/7/6/1/7615b84a11cd1887e35bcdf2e5bdb9bb82.png)
Дуги B-D, D-T насыщены

Шаг 6. Рассмотрим путь S-A-C-T. Можем увеличить поток на величину
![$% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciyBaiaacM
% gacaGGUbWaaeWaaeaacaaI1aGaaiilaiaaikdacqGHsislcaaIZaGa
% aiilaiaaikdacaGG7aGaaGymaiaacYcacaaIXaGaai4oaiaaiodaca
% GGSaGaaGOmaiabgkHiTiaaikdacaGGSaGaaGOmaaGaayjkaiaawMca
% aiabg2da9iaaigdacaGGSaGaaGimaaaa!4B96!
\[
\min \left( {5,2 - 3,2;1,1;3,2 - 2,2} \right) = 1,0
\]
$ $% MathType!MTEF!2!1!+-
% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciyBaiaacM
% gacaGGUbWaaeWaaeaacaaI1aGaaiilaiaaikdacqGHsislcaaIZaGa
% aiilaiaaikdacaGG7aGaaGymaiaacYcacaaIXaGaai4oaiaaiodaca
% GGSaGaaGOmaiabgkHiTiaaikdacaGGSaGaaGOmaaGaayjkaiaawMca
% aiabg2da9iaaigdacaGGSaGaaGimaaaa!4B96!
\[
\min \left( {5,2 - 3,2;1,1;3,2 - 2,2} \right) = 1,0
\]
$](https://dxdy-01.korotkov.co.uk/f/c/4/5/c45614701160a7aef6a8a2a468d0c0ab82.png)
Тогда поток
Дуга C-T становится насыщенной.

Т.о., больше не существует путей из S в T.
Значит максимальный поток равен 9,6.
Верны ли мои рассуждения?
В задании сказано, что надо найти ещё разрез с минимальной пропускной способностью. Как найти этот разрез?