src/HOL/Real/HahnBanach/FunctionOrder.thy
changeset 8203 2fcc6017cb72
parent 7978 1b99ee57d131
child 9035 371f023d3dbd
equal deleted inserted replaced
8202:f32931b93686 8203:2fcc6017cb72
    22 
    22 
    23 constdefs
    23 constdefs
    24   graph :: "['a set, 'a => real] => 'a graph "
    24   graph :: "['a set, 'a => real] => 'a graph "
    25   "graph F f == {(x, f x) | x. x:F}"; 
    25   "graph F f == {(x, f x) | x. x:F}"; 
    26 
    26 
    27 lemma graphI [intro!!]: "x:F ==> (x, f x) : graph F f";
    27 lemma graphI [intro??]: "x:F ==> (x, f x) : graph F f";
    28   by (unfold graph_def, intro CollectI exI) force;
    28   by (unfold graph_def, intro CollectI exI) force;
    29 
    29 
    30 lemma graphI2 [intro!!]: "x:F ==> EX t: (graph F f). t = (x, f x)";
    30 lemma graphI2 [intro??]: "x:F ==> EX t: (graph F f). t = (x, f x)";
    31   by (unfold graph_def, force);
    31   by (unfold graph_def, force);
    32 
    32 
    33 lemma graphD1 [intro!!]: "(x, y): graph F f ==> x:F";
    33 lemma graphD1 [intro??]: "(x, y): graph F f ==> x:F";
    34   by (unfold graph_def, elim CollectE exE) force;
    34   by (unfold graph_def, elim CollectE exE) force;
    35 
    35 
    36 lemma graphD2 [intro!!]: "(x, y): graph H h ==> y = h x";
    36 lemma graphD2 [intro??]: "(x, y): graph H h ==> y = h x";
    37   by (unfold graph_def, elim CollectE exE) force; 
    37   by (unfold graph_def, elim CollectE exE) force; 
    38 
    38 
    39 subsection {* Functions ordered by domain extension *};
    39 subsection {* Functions ordered by domain extension *};
    40 
    40 
    41 text{* A function $h'$ is an extension of $h$, iff the graph of 
    41 text{* A function $h'$ is an extension of $h$, iff the graph of 
    44 lemma graph_extI: 
    44 lemma graph_extI: 
    45   "[| !! x. x: H ==> h x = h' x; H <= H'|]
    45   "[| !! x. x: H ==> h x = h' x; H <= H'|]
    46   ==> graph H h <= graph H' h'";
    46   ==> graph H h <= graph H' h'";
    47   by (unfold graph_def, force);
    47   by (unfold graph_def, force);
    48 
    48 
    49 lemma graph_extD1 [intro!!]: 
    49 lemma graph_extD1 [intro??]: 
    50   "[| graph H h <= graph H' h'; x:H |] ==> h x = h' x";
    50   "[| graph H h <= graph H' h'; x:H |] ==> h x = h' x";
    51   by (unfold graph_def, force);
    51   by (unfold graph_def, force);
    52 
    52 
    53 lemma graph_extD2 [intro!!]: 
    53 lemma graph_extD2 [intro??]: 
    54   "[| graph H h <= graph H' h' |] ==> H <= H'";
    54   "[| graph H h <= graph H' h' |] ==> H <= H'";
    55   by (unfold graph_def, force);
    55   by (unfold graph_def, force);
    56 
    56 
    57 subsection {* Domain and function of a graph *};
    57 subsection {* Domain and function of a graph *};
    58 
    58