GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it
Eval Rules
if IsEqualAsMorphism( Precompose( tau_alpha, alpha ), Precompose( tau_beta, beta ) ) then
Precompose( UniversalMorphismIntoFiberProduct( FiberProduct( alpha, beta ), tau_alpha, tau_beta ), ProjectionInFactor( FiberProduct( alpha, beta ), 1 ) ) -> tau_alpha
theorem1.32 := rec( Source := [ Precompose,
[ UniversalMorphismIntoFiberProduct,
[ FiberProduct,
"alpha",
"beta"
],
"tau_alpha",
"tau_beta"
],
[ ProjectionInFactor,
[ FiberProduct,
"alpha",
"beta"
],
1
]
],
Range := "tau_alpha",
Condition := [ IsEqualAsMorphism,
[ Precompose,
"tau_alpha",
"alpha"
],
[ Precompose,
"tau_beta",
"beta"
]
]
);
Immediate Rules
@Theorem
A | .
theorem1.14 := rec( Source_List := [ rec( Source := "beta,
Source_predicate := IsMonomorphism,
value := true ) ],
Range := [ ProjectionInFactor,
[ FiberProduct,
"alpha",
"beta"
]
1
],
Range_predicate := IsMonomorphism,
value := true );
True Rules
theorem 1.1 := rec( Source_Filters := [ IsZero, OBJECT_FILTER ],
Range_Filters := [ IsInjective, OBJECT_FILTER ] );