查看“︁SDO”︁的源代码

SDO（Small Dropping Ordinal），由 Username5243 命名<ref>https://googology.fandom.com/wiki/User:Username5243/Username%27s_OCF</ref>，指代原版 [[UNOCF]] 极限，同时也是 [[Dropping Hydra|N-dropping]] 和 [[N-shifting]] 模式的极限。
{| class="wikitable"
![[序数记号]]
!表达式
|-
|[[稳定序数]]
|<math>\psi(\lambda\alpha.\Omega_{\alpha+\omega}-\Pi_0)</math>
|-
|[[投影序数]]
|<math>\psi(\psi_\alpha(\Omega_{\alpha+\omega}))</math>
|-
|[[投影序数#向上投影|向上投影]]
|<math>\psi(\psi_S(\sigma S*2+\psi_{S_3}(\sigma S+1)))</math>
|-
|[[UNOCF]]
|<math>\psi(C(1\{\omega\}0)))</math>
|-
|[[BMS]]
|<math>(0)(1,1,1)(2,2,1)(3)</math>
|-
|[[0-Y]]
|<math>1,4,9,10</math>
|-
|[[Y序列|1-Y]]
|<math>1,2,4,8,15,16</math>
|-
|[[Ex-hydra]]
|<math>p1(p3(p5(p1))))</math>
|-
|[[Fake Fake Fake Zeta]]
|<math>\psi_\Zeta[\varepsilon_1,\psi_\Zeta[\varepsilon_0,\varepsilon_0\times\omega](\varepsilon_0\times\omega)](\psi_\Zeta[\varepsilon_0,\varepsilon_0\times\omega](\varepsilon_0\times\omega))</math>
|}

=== 性质 ===
极限在此处的记号：[[SAN]]，R函数，[[Dropping Hydra]] 等 [[Dropping Hydra|N-dropping]]记号，[[TON]] 主记号等 [[N-shifting]] 记号，[[UNOCF]] 等多逗号模式记号，LPrSS Hydra
<references />
[[分类:序数]]