exercise 56.1.
Use two identities 𝐴 ⊢𝐴, combine their disjoint contexts with tensor introduction to obtain 𝐴,𝐴 ⊢𝐴 ⊗𝐴, and apply rank-2 multiplexing to conclude !𝐴 ⊢𝐴 ⊗𝐴. For the additive formula, apply rank-1 multiplexing separately to two copies of the identity derivation, obtaining two derivations of !𝐴 ⊢𝐴; additive conjunction introduction reuses that same context and concludes !𝐴 ⊢𝐴&𝐴. Rank 0 exposes no copy and therefore acts as weakening.
exercise 56.2.
First 𝑊𝑢&𝑣 =𝑋 +2 +3 +1 =𝑋 +6. Boxing gives 𝑊!(𝑢&𝑣) =𝑋2 +6𝑋 +1, which evaluates to 17 at rank 2. Its degree is one more than the larger degree of 𝑢 and 𝑣.
exercise 56.3.
At rank 2, the family has bounds 𝑘𝑚2𝑚. Since the exponent 𝑚 grows with the encoded net, no fixed-degree polynomial covers the family by the corollary. The changed hypothesis is that 𝑢, and hence its degree, was fixed.
exercise 56.4.
The degrees are 2 and 3, so the representation sequent is 𝖲(6) ⊢𝖡: it has six string assumptions. Coefficients change how many fixed transition components are composed; the number of antecedent copies records polynomial degrees, not coefficients.
exercise 56.5.
Licensed: a fixed rank-𝑛 net 𝑢 normalizes in at most 𝑊𝑢(𝑛) external steps. Not licensed: a source function on a numeric input 𝑥 runs in at most 3𝑥 +2 steps because its type carries that potential. The first quantity is proof-net weight at rank; the second would be input-indexed operational cost.
exercise 56.6.
Under the mutated equation, 𝑊𝗆!𝑣(3)=𝑊𝑣(3)+1=4,𝑊𝗆!!𝑣(3)=𝑊𝗆!𝑣(3)+1=5. Opening the outer box may create three copies of !𝑣, whose combined mutated weight is 3 ⋅4 =12 >5. The missing factor of 𝑋 was the charge for multiplexing.
exercise 56.7.
Rank 0 exposes no copy of 𝐴, rank 1 exposes one, and rank 2 exposes two, giving weakening, dereliction, and binary contraction behavior. Each rule removes one !𝐴 on the left; none derives !!𝐴 from !𝐴, which would be digging.
exercise 56.8.
A principal multiplicative interaction removes at least one right-logical cell of weight 1, while left cells have weight 0. For an exponential cut against rank 𝑞 ≤𝑛, the redex charge is 𝑛𝑊𝑤(𝑛) +1 and the copies cost at most 𝑞𝑊𝑤(𝑛); the decrease is at least one. Commuting independent cells does not change either calculation.
exercise 56.9.
A fixed degree-3 net has bound 𝑘𝑛3 as rank 𝑛 varies. A family with degree equal to input length has a bound of the form 𝑘𝑛𝑛𝑛, with changing coefficient and exponent; the fixed-program hypothesis needed for one polynomial is absent.
exercise 56.10.
Linear time has degree 1 and constant space degree 0, so the theorem gives 𝖲(2) ⊢𝖡. The construction needs a string encoding, length iterator, fixed transition net, constant-size tape/state encoding, iteration composition, and accepting-state Boolean observation.