| Some definitions of interest. |
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inject | Def Inj(A; B; f) == a1,a2:A. f(a1) = f(a2) B ![](FONT/eq.png) a1 = a2 |
| | Thm* A,B:Type, f:(A![](FONT/dash.png) B). Inj(A; B; f) Prop |
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inv_funs_2 | Def InvFuns(A;B;f;g) == ( x:A. g(f(x)) = x) & ( y:B. f(g(y)) = y) |
| | Thm* f:(A![](FONT/dash.png) B), g:(B![](FONT/dash.png) A). InvFuns(A;B;f;g) Prop |
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surject | Def Surj(A; B; f) == b:B. a:A. f(a) = b |
| | Thm* A,B:Type, f:(A![](FONT/dash.png) B). Surj(A; B; f) Prop |