Theorem dffun6 6372

Description: Alternate definition of a function using "at most one" notation. (Contributed by NM, 9-Mar-1995.)

Assertion

Ref	Expression
dffun6	⊢ (Fun 𝐹 ↔ (Rel 𝐹 ∧ ∀𝑥∃*𝑦 𝑥𝐹𝑦))

Distinct variable group:   𝑥,𝑦,𝐹

Proof of Theorem dffun6

Step	Hyp	Ref	Expression
1		nfcv 2979	. 2 ⊢ Ⅎ𝑥𝐹
2		nfcv 2979	. 2 ⊢ Ⅎ𝑦𝐹
3	1, 2	dffun6f 6371	1 ⊢ (Fun 𝐹 ↔ (Rel 𝐹 ∧ ∀𝑥∃*𝑦 𝑥𝐹𝑦))

Syntax hints:   ↔ wb 208   ∧ wa 398  ∀wal 1535  ∃*wmo 2620   class class class wbr 5068  Rel wrel 5562  Fun wfun 6351

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2116  ax-9 2124  ax-10 2145  ax-11 2161  ax-12 2177  ax-ext 2795  ax-sep 5205  ax-nul 5212  ax-pr 5332

This theorem depends on definitions:  df-bi 209  df-an 399  df-or 844  df-3an 1085  df-tru 1540  df-ex 1781  df-nf 1785  df-sb 2070  df-mo 2622  df-eu 2654  df-clab 2802  df-cleq 2816  df-clel 2895  df-nfc 2965  df-ral 3145  df-rab 3149  df-v 3498  df-dif 3941  df-un 3943  df-in 3945  df-ss 3954  df-nul 4294  df-if 4470  df-sn 4570  df-pr 4572  df-op 4576  df-br 5069  df-opab 5131  df-id 5462  df-cnv 5565  df-co 5566  df-fun 6359

This theorem is referenced by:  funmo  6373  dffun7  6384  fununfun  6404  funcnvsn  6406  funcnv2  6424  svrelfun  6428  fnres  6476  nfunsn  6709  dff3  6868  brdom3  9952  nqerf  10354  shftfn  14434  cnextfun  22674  perfdvf  24503  taylf  24951  funressnvmo  43287