# from the theory of proveit.core_expr_types¶

In [1]:
import proveit
# Automation is not needed when building an expression:
proveit.defaults.automation = False # This will speed things up.
proveit.defaults.inline_pngs = False # Makes files smaller.
# import Expression classes needed to build the expression
from proveit import ExprRange, Function, Variable, f, i, j
from proveit.logic import Equals
from proveit.numbers import one, subtract

In [2]:
# build up the expression from sub-expressions
sub_expr1 = Variable("_a", latex_format = r"{_{-}a}")
sub_expr2 = Function(f, [sub_expr1])
expr = Equals([ExprRange(sub_expr1, sub_expr2, i, j)], [ExprRange(sub_expr1, sub_expr2, i, subtract(j, one)), Function(f, [j])]).with_wrapping_at(2)

expr:
In [3]:
# check that the built expression is the same as the stored expression
assert expr == stored_expr
assert expr._style_id == stored_expr._style_id
print("Passed sanity check: expr matches stored_expr")

Passed sanity check: expr matches stored_expr

In [4]:
# Show the LaTeX representation of the expression for convenience if you need it.
print(stored_expr.latex())

\begin{array}{c} \begin{array}{l} \left(f\left(i\right), f\left(i + 1\right), \ldots, f\left(j\right)\right) =  \\ \left(f\left(i\right), f\left(i + 1\right), \ldots, f\left(j - 1\right), f\left(j\right)\right) \end{array} \end{array}

In [5]:
stored_expr.style_options()

namedescriptiondefaultcurrent valuerelated methods
operation'infix' or 'function' style formattinginfixinfix
wrap_positionsposition(s) at which wrapping is to occur; '2 n - 1' is after the nth operand, '2 n' is after the nth operation.()(2)('with_wrapping_at', 'with_wrap_before_operator', 'with_wrap_after_operator', 'without_wrapping', 'wrap_positions')
justificationif any wrap positions are set, justify to the 'left', 'center', or 'right'centercenter('with_justification',)
directionDirection of the relation (normal or reversed)normalnormal('with_direction_reversed', 'is_reversed')
In [6]:
# display the expression information
stored_expr.expr_info()

core typesub-expressionsexpression
0Operationoperator: 1
operands: 2
1Literal
2ExprTuple3, 4
3ExprTuple5
4ExprTuple6, 7
5ExprRangelambda_map: 8
start_index: 9
end_index: 17
6ExprRangelambda_map: 8
start_index: 9
end_index: 10
7Operationoperator: 15
operand: 17
8Lambdaparameter: 19
body: 12
9Variable
10Operationoperator: 13
operands: 14
11ExprTuple17
12Operationoperator: 15
operand: 19
13Literal
14ExprTuple17, 18
15Variable
16ExprTuple19
17Variable
18Operationoperator: 20
operand: 22
19Variable
20Literal
21ExprTuple22
22Literal