begin
theorem Th1:
theorem Th2:
theorem Th3:
theorem Th4:
theorem Th5:
theorem Th6:
theorem Th7:
Lm1:
<*1,2*> <> <*2,1*>
by FINSEQ_1:98;
theorem Th8:
theorem
theorem Th10:
theorem Th11:
theorem
for
K being
Field for
M being
Matrix of 2,
K holds
Det M = ((M * (1,1)) * (M * (2,2))) - ((M * (1,2)) * (M * (2,1)))
theorem Th13:
theorem Th14:
theorem
:: deftheorem Def1 defines IFIN MATRIX_7:def 1 :
for x, y, a, b being set holds
( ( x in y implies IFIN (x,y,a,b) = a ) & ( not x in y implies IFIN (x,y,a,b) = b ) );
theorem
:: deftheorem Def2 defines diagonal MATRIX_7:def 2 :
for n being Nat
for K being Field
for M being Matrix of n,K holds
( M is diagonal iff for i, j being Element of NAT st i in Seg n & j in Seg n & i <> j holds
M * (i,j) = 0. K );
theorem
theorem Th18:
theorem Th19:
:: deftheorem defines @ MATRIX_7:def 3 :
for n being Nat
for K being Field
for A being Matrix of n,K holds A @ = A @ ;
theorem
:: deftheorem Def4 defines " MATRIX_7:def 4 :
for G being Group
for f, b3 being FinSequence of G holds
( b3 = f " iff ( len b3 = len f & ( for i being Element of NAT st i in dom f holds
b3 /. i = (f /. i) " ) ) );
theorem Th21:
theorem Th22:
theorem Th23:
theorem Th24:
theorem Th25:
theorem Th26:
theorem Th27:
Lm2:
for n being Element of NAT
for IT being Element of Permutations n st IT is even & n >= 1 holds
IT " is even
theorem Th28:
theorem Th29:
theorem
theorem Th31:
theorem Th32:
theorem
theorem Th34:
theorem Th35:
theorem Th36:
theorem