Theorem elArrow | index | src |

theorem elArrow (A B: set) (f: nat): $ f e. Arrow A B <-> func f A B $;
StepHypRefExpression
1 id
_1 = f -> _1 = f
2 1 nseqd
_1 = f -> _1 == f
3 2 isfeqd
_1 = f -> (isfun _1 <-> isfun f)
4 2 dmeqd
_1 = f -> Dom _1 == Dom f
5 4 eqseq1d
_1 = f -> (Dom _1 == A <-> Dom f == A)
6 3, 5 aneqd
_1 = f -> (isfun _1 /\ Dom _1 == A <-> isfun f /\ Dom f == A)
7 2 rneqd
_1 = f -> Ran _1 == Ran f
8 7 sseq1d
_1 = f -> (Ran _1 C_ B <-> Ran f C_ B)
9 6, 8 aneqd
_1 = f -> (isfun _1 /\ Dom _1 == A /\ Ran _1 C_ B <-> isfun f /\ Dom f == A /\ Ran f C_ B)
10 9 conv func
_1 = f -> (isfun _1 /\ Dom _1 == A /\ Ran _1 C_ B <-> func f A B)
11 10 elabe
f e. {_1 | isfun _1 /\ Dom _1 == A /\ Ran _1 C_ B} <-> func f A B
12 11 conv Arrow
f e. Arrow A B <-> func f A B

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)