Theorem elrapp | index | src |

theorem elrapp (F: set) (a b: nat): $ b e. F @' a <-> a, b e. F $;
StepHypRefExpression
1 eqidd
_1 = b -> a = a
2 id
_1 = b -> _1 = b
3 1, 2 preqd
_1 = b -> a, _1 = a, b
4 eqsidd
_1 = b -> F == F
5 3, 4 eleqd
_1 = b -> (a, _1 e. F <-> a, b e. F)
6 5 elabe
b e. {_1 | a, _1 e. F} <-> a, b e. F
7 6 conv rapp
b e. F @' a <-> a, b e. F

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp, itru), axs_pred_calc (ax_gen, ax_4, ax_5, ax_6, ax_7, ax_10, ax_11, ax_12), axs_set (elab, ax_8), axs_the (theid, the0), axs_peano (peano2, addeq, muleq)